Non-local home directory fails with permission errors

If I run uck on a server where my home dir is automounted via NFS, I get:

0 %> Preparing build environment...
Creating X authentication cookie...
No matches found, authority file "-" not written
Running build process...
Ubuntu Customization Kit 2.0.8
Starting CD remastering on Fri Jul 31 10:26:59 PDT 2009
Customization dir=/users/bedge/tmp/customization-scripts
Mounting ISO image...
mkdir: cannot create directory `/users/bedge/tmp/iso-mount': Permission denied
Cannot create directory /users/bedge/tmp/iso-mount, error=1

Even if I chmod 777 ~/tmp it later fails with:

 %> Preparing build environment...
Creating X authentication cookie...
No matches found, authority file "-" not written
Running build process...
Ubuntu Customization Kit 2.0.8
Starting CD remastering on Fri Jul 31 10:33:04 PDT 2009
Customization dir=/users/bedge/tmp/customization-scripts
Removing ISO remastering dir...
Mounting ISO image...
Unpacking ISO image...
cp: failed to preserve ownership for `/users/bedge/tmp/remaster-iso/autorun.inf': Operation not permitted
cp: failed to preserve ownership for `/users/bedge/tmp/remaster-iso/casper/filesystem.manifest': Operation not permitted
cp: failed to preserve ownership for `/users/bedge/tmp/remaster-iso/casper/filesystem.manifest-desktop': Operation not permitted

Running on a local machine did not have these problems.