Hi,
I tried to reproduce this issue, but it worked well for me.
Did you find some related error form 12 hive? Did you customize on this document library?
Check whether this issue is particular and isolate.
Check whether there are lookup fileds leading to this issue, refer to the similar post,
http://social.technet.microsoft.com/Forums/en-US/sharepointgeneral/thread/a36f7b72-9b4d-4f16-aea8-7d08b1594096/
Thanks
Daniel Yang
TechNet Community Support
