cant mount kerberized nfs4 shares anymore on gutsy

We have a kerberized nfs4 share hosted on our debian etch server and so far we've had no problems at all mounting it on our feisty workstations. But I had no luck on gutsy. Mounting leads to a permission denied. Syslog reports the following:

Oct 8 16:34:17 ws-05 rpc.gssd[4114]: handling krb5 upcall
Oct 8 16:34:18 ws-05 rpc.gssd[4114]: Full hostname for 'svc.corsaroconsulting.com' is 'svc.corsaroconsulting.com'
Oct 8 16:34:18 ws-05 rpc.gssd[4114]: Full hostname for 'ws-05.corsaroconsulting.com' is 'ws-05.corsaroconsulting.com'
Oct 8 16:34:18 ws-05 rpc.gssd[4114]: Key table entry not found while getting keytab entry for 'root/ws-05.corsaroconsulting.com@'
Oct 8 16:34:18 ws-05 rpc.gssd[4114]: Success getting keytab entry for 'nfs/ws-05.corsaroconsulting.com@'
Oct 8 16:34:18 ws-05 rpc.gssd[4114]: INFO: Credentials in CC 'FILE:/tmp/krb5cc_machine_CORSAROCONSULTING.COM' are good until 1191878643
Oct 8 16:34:18 ws-05 rpc.gssd[4114]: INFO: Credentials in CC 'FILE:/tmp/krb5cc_machine_CORSAROCONSULTING.COM' are good until 1191878643
Oct 8 16:34:18 ws-05 rpc.gssd[4114]: using FILE:/tmp/krb5cc_machine_CORSAROCONSULTING.COM as credentials cache for machine creds
Oct 8 16:34:18 ws-05 rpc.gssd[4114]: using environment variable to select krb5 ccache FILE:/tmp/krb5cc_machine_CORSAROCONSULTING.COM
Oct 8 16:34:18 ws-05 rpc.gssd[4114]: creating context using fsuid 0 (save_uid 0)
Oct 8 16:34:18 ws-05 rpc.gssd[4114]: creating tcp client for server svc.corsaroconsulting.com
Oct 8 16:34:18 ws-05 rpc.gssd[4114]: creating context with server <email address hidden>
Oct 8 16:34:18 ws-05 rpc.gssd[4114]: in authgss_create_default()
Oct 8 16:34:18 ws-05 rpc.gssd[4114]: in authgss_create()
Oct 8 16:34:18 ws-05 rpc.gssd[4114]: authgss_create: name is 0x8056748
Oct 8 16:34:18 ws-05 rpc.gssd[4114]: authgss_create: gd->name is 0x806c8c8
Oct 8 16:34:18 ws-05 rpc.gssd[4114]: in authgss_refresh()
Oct 8 16:34:18 ws-05 rpc.gssd[4114]: struct rpc_gss_sec:
Oct 8 16:34:18 ws-05 rpc.gssd[4114]: mechanism_OID: { 1 2 134 72 134 247 18 1 2 2 }
Oct 8 16:34:18 ws-05 rpc.gssd[4114]: qop: 0
Oct 8 16:34:18 ws-05 rpc.gssd[4114]: service: 1
Oct 8 16:34:18 ws-05 rpc.gssd[4114]: cred: 0x806b3c0
Oct 8 16:34:18 ws-05 rpc.gssd[4114]: req_flags: 00000002
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: The token being sent (length 644):
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 0000: 6082 0280 0609 2a86 4886 f712 0102 0201 `.....*.H.......
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 0010: 006e 8202 6f30 8202 6ba0 0302 0105 a103 .n..o0..k.......
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 0020: 0201 0ea2 0703 0500 2000 0000 a382 015f ........ ......_
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 0030: 6182 015b 3082 0157 a003 0201 05a1 171b a..[0..W........
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 0040: 1543 4f52 5341 524f 434f 4e53 554c 5449 .CORSAROCONSULTI
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 0050: 4e47 2e43 4f4d a22b 3029 a003 0201 03a1 NG.COM.+0)......
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 0060: 2230 201b 036e 6673 1b19 7376 632e 636f "0 ..nfs..svc.co
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 0070: 7273 6172 6f63 6f6e 7375 6c74 696e 672e rsaroconsulting.
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 0080: 636f 6da3 8201 0830 8201 04a0 0302 0110 com....0........
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 0090: a103 0201 04a2 81f7 0481 f4d3 8c0e ed73 ...............s
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 00a0: a532 7923 b5a1 7df0 d44a 2f53 0f01 96b6 .2y#..}..J/S....
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 00b0: ea3e 427a 713d 0ff8 121b 061e 6325 8fd1 .>Bzq=......c%..
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 00c0: 4c62 dea6 1ce3 c5db eb3e 73b4 91ba 9775 Lb.......>s....u
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 00d0: 405b 86b2 e259 ab73 be5d f75e eab9 60de @[...Y.s.].^..`.
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 00e0: 45df 4d55 f110 6d1d 1b09 df57 99fb e95d E.MU..m....W...]
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 00f0: 9836 8376 08c8 357f 71b7 7099 cd3e 7136 .6.v..5.q.p..>q6
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 0100: 9227 a5eb 3699 8057 25bc dabd 82c6 1ad4 .'..6..W%.......
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 0110: a91b aed7 f962 fd31 5a3f 62fe 5162 d4f4 .....b.1Z?b.Qb..
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 0120: dd5f 8827 5cb8 4d2c 12c0 2365 de27 618a ._.'\.M,..#e.'a.
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 0130: bcb4 ae44 b61a c419 09e5 521d ec83 3ca7 ...D......R...<.
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 0140: 7701 03fa 6139 7d51 8fd8 1820 e0cc e45f w...a9}Q... ..._
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 0150: b496 758e bb58 2bfe 9149 8295 10f5 81c2 ..u..X+..I......
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 0160: 270f 1718 c8af 9744 c1d7 29dc 5d53 8ea9 '......D..).]S..
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 0170: 3394 6960 a191 9dbe 83dc 0f54 20d9 fcd4 3.i`.......T ...
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 0180: 7377 7536 4033 0f98 2b5b 5164 ba7b 32a4 swu6@3..+[Qd.{2.
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 0190: 81f2 3081 efa0 0302 0110 a281 e704 81e4 ..0.............
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 01a0: f20c 97ba 7441 6e3d 9540 0520 59b3 ef3c ....tAn=.@. Y..<
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 01b0: 26a4 2a9b 4579 a574 ef74 b618 536c f36c &.*.Ey.t.t..Sl.l
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 01c0: 1334 935f bc3e 5e2d 03ac ccbd 9ace 3983 .4._.>^-......9.
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 01d0: f6b5 a949 9b5a d80f 80d0 8139 4218 f56b ...I.Z.....9B..k
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 01e0: 97d4 3a34 f23d f2e7 1cd1 34eb 0f5a 38cf ..:4.=....4..Z8.
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 01f0: a9b0 3fa9 236a 8db2 c0ad ad8d 9ec4 79a4 ..?.#j........y.
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 0200: 180d 67db cf92 659e 3dd8 d22e c197 a4d0 ..g...e.=.......
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 0210: c4c8 bf62 aef5 034c 2174 6469 0adf 5e28 ...b...L!tdi..^(
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 0220: a149 6ac1 01c4 9327 6b91 5241 4ca9 070d .Ij....'k.RAL...
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 0230: f6af 646c 861a 09a5 a4da 29c4 52cb b258 ..dl......).R..X
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 0240: 15cb 5cf8 c2e8 c8a3 8f25 cec5 414a f9f8 ..\......%..AJ..
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 0250: 1aba 76bf b8af 1e5e 60d1 96d6 fa28 fd0a ..v....^`....(..
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 0260: 809c 0b2c 01f4 d56f 2a7e a72c d1cf 939a ...,...o*~.,....
Oct 8 16:34:19 ws-05 rpc.gssd[4114]: 0270: 5f61 f862 df47 39f8 cb54 ac88 a5aa 6c74 _a.b.G9..T....lt
Oct 8 16:34:20 ws-05 rpc.gssd[4114]: 0280: 62fb 7a41 b.zA
Oct 8 16:34:20 ws-05 rpc.gssd[4114]: in authgss_marshal()
Oct 8 16:34:20 ws-05 rpc.gssd[4114]: xdr_rpc_gss_buf: encode success ((nil):0)
Oct 8 16:34:20 ws-05 rpc.gssd[4114]: xdr_rpc_gss_cred: encode success (v 1, proc 1, seq 0, svc 1, ctx (nil):0)
Oct 8 16:34:20 ws-05 rpc.gssd[4114]: in authgss_wrap()
Oct 8 16:34:20 ws-05 rpc.gssd[4114]: xdr_rpc_gss_buf: encode success (0x806d420:644)
Oct 8 16:34:20 ws-05 rpc.gssd[4114]: xdr_rpc_gss_init_args: encode success (token 0x806d420:644)
Oct 8 16:34:20 ws-05 rpc.gssd[4114]: in authgss_validate()
Oct 8 16:34:20 ws-05 rpc.gssd[4114]: in authgss_unwrap()
Oct 8 16:34:20 ws-05 rpc.gssd[4114]: xdr_rpc_gss_buf: decode success (0x8057dc0:4)
Oct 8 16:34:20 ws-05 rpc.gssd[4114]: xdr_rpc_gss_buf: decode success (0x806d6a8:153)
Oct 8 16:34:20 ws-05 rpc.gssd[4114]: xdr_rpc_gss_init_res decode success (ctx 0x8057dc0:4, maj 524288, min 0, win 128, token 0x806d6a8:153)
Oct 8 16:34:20 ws-05 rpc.gssd[4114]: authgss_create_default: freeing name 0x8056748
Oct 8 16:34:20 ws-05 rpc.gssd[4114]: WARNING: Failed to create krb5 context for user with uid 0 for server svc.corsaroconsulting.com
Oct 8 16:34:20 ws-05 rpc.gssd[4114]: WARNING: Failed to create krb5 context for user with uid 0 with credentials cache FILE:/tmp/krb5cc_machine_CORSAROCONSULTING.COM for server svc.corsaroconsulting.com
Oct 8 16:34:20 ws-05 rpc.gssd[4114]: WARNING: Failed to create krb5 context for user with uid 0 with any credentials cache for server svc.corsaroconsulting.com
Oct 8 16:34:20 ws-05 rpc.gssd[4114]: doing error downcall
Oct 8 16:34:20 ws-05 rpc.gssd[4114]: destroying client clnt7
Oct 8 16:34:20 ws-05 rpc.gssd[4114]: destroying client clnt6

this is what klist -c /tmp/<machinecredentialscachefile> reports:

Ticket cache: FILE:/tmp/krb5cc_machine_CORSAROCONSULTING.COM
Default principal: <email address hidden>

Valid starting Expires Service principal
10/08/07 13:24:03 10/08/07 23:24:03 <email address hidden>
        renew until 10/09/07 13:24:03
10/08/07 13:24:04 10/08/07 23:24:03 nfs/svc.corsaroconsulting.com@
        renew until 10/09/07 13:24:03
10/08/07 16:33:50 10/08/07 23:24:03 nfs/svc.corsaroconsulting.com@
        renew until 10/09/07 13:24:03
10/08/07 16:33:54 10/08/07 23:24:03 nfs/svc.corsaroconsulting.com@
        renew until 10/09/07 13:24:03
10/08/07 16:34:18 10/08/07 23:24:03 nfs/svc.corsaroconsulting.com@
        renew until 10/09/07 13:24:03

can't understand why the realm name is missing after the @

regards, Andrea