Enlistment fails with "400 BAD REQUEST" in logs

I've recently rebuilt a MAAS server, replacing a development branch in an lxc container with a regular build (14.04 RC) version running directly from packages on the main system. Unfortunately, when I attempt to enlist a node, it receives a DHCP lease but then fails to PXE-boot. I'm attaching the /var/log/maas directory tree. I've noticed a huge number of OOPS logs and multiple blocks like the following in pserv.log:

2014-04-10 19:40:48-0400 [HTTPPageGetter,client] Stopping factory <HTTPClientFact
ory: http:///MAAS/api/1.0/pxeconfig/?cluster_uuid=3eac1224-3620-4003-8fe7-5e3a4b8
37aff&local=10.0.0.1&remote=10.0.0.52>
2014-04-10 19:40:48-0400 [HTTPPageGetter,client] Stopping factory <HTTPClientFact
ory: http:///MAAS/api/1.0/pxeconfig/?cluster_uuid=3eac1224-3620-4003-8fe7-5e3a4b8
37aff&local=10.0.0.1&remote=10.0.0.52>
2014-04-10 19:40:48-0400 [HTTPPageGetter,client] Logged OOPS id OOPS-85939f7235a6
b85da8a1f1d400555164: No exception type: No exception value
2014-04-10 19:40:48-0400 [HTTPPageGetter,client] Logged OOPS id OOPS-dec46fed997c
d2122c2fe8469ca301d1: Error: 400 BAD REQUEST
2014-04-10 19:40:55-0400 [-] Starting factory <HTTPClientFactory: http://10.0.0.1
/MAAS/rpc/>
2014-04-10 19:40:55-0400 [-] Starting factory <HTTPClientFactory: http://10.0.0.1
/MAAS/rpc/>
2014-04-10 19:40:55-0400 [HTTPPageGetter,client] Stopping factory <HTTPClientFact
ory: http://10.0.0.1/MAAS/rpc/>
2014-04-10 19:40:55-0400 [HTTPPageGetter,client] Stopping factory <HTTPClientFact
ory: http://10.0.0.1/MAAS/rpc/>
2014-04-10 19:41:01-0400 [TFTP (UDP)] Datagram received from ('10.0.0.52', 49162)
: <RRQDatagram(filename=pxelinux.cfg/default, mode=octet, options={'tsize': '0',
'blksize': '1408'})>
2014-04-10 19:41:01-0400 [TFTP (UDP)] Datagram received from ('10.0.0.52', 49162)
: <RRQDatagram(filename=pxelinux.cfg/default, mode=octet, options={'tsize': '0',
'blksize': '1408'})>
2014-04-10 19:41:01-0400 [-] Starting factory <HTTPClientFactory: http:///MAAS/ap
i/1.0/pxeconfig/?cluster_uuid=3eac1224-3620-4003-8fe7-5e3a4b837aff&local=10.0.0.1
&remote=10.0.0.52>
2014-04-10 19:41:01-0400 [-] Starting factory <HTTPClientFactory: http:///MAAS/ap
i/1.0/pxeconfig/?cluster_uuid=3eac1224-3620-4003-8fe7-5e3a4b837aff&local=10.0.0.1
&remote=10.0.0.52>
2014-04-10 19:41:01-0400 [HTTPPageGetter,client] Unhandled error in Deferred:
2014-04-10 19:41:01-0400 [HTTPPageGetter,client] Unhandled Error
        Traceback (most recent call last):
        Failure: twisted.web.error.Error: 400 BAD REQUEST

Here are my packages:

$ dpkg -l '*maas*'|cat
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Architecture Description
+++-===================================-=======================================-============-===============================================================================
ii maas 1.5+bzr2236+2238+274~ppa0~ubuntu14.04.1 all MAAS server all-in-one metapackage
ii maas-cli 1.5+bzr2236+2238+274~ppa0~ubuntu14.04.1 all MAAS command line API tool
ii maas-cluster-controller 1.5+bzr2236+2238+274~ppa0~ubuntu14.04.1 all MAAS server cluster controller
ii maas-common 1.5+bzr2236+2238+274~ppa0~ubuntu14.04.1 all MAAS server common files
ii maas-dhcp 1.5+bzr2236+2238+274~ppa0~ubuntu14.04.1 all MAAS DHCP server
ii maas-dns 1.5+bzr2236+2238+274~ppa0~ubuntu14.04.1 all MAAS DNS server
ii maas-region-controller 1.5+bzr2236+2238+274~ppa0~ubuntu14.04.1 all MAAS server complete region controller
ii maas-region-controller-min 1.5+bzr2236+2238+274~ppa0~ubuntu14.04.1 all MAAS Server minimum region controller
ii python-django-maas 1.5+bzr2236+2238+274~ppa0~ubuntu14.04.1 all MAAS server Django web framework
ii python-maas-client 1.5+bzr2236+2238+274~ppa0~ubuntu14.04.1 all MAAS python API client
ii python-maas-provisioningserver 1.5+bzr2236+2238+274~ppa0~ubuntu14.04.1 all MAAS server provisioning libraries