There is a known issue with Mac OS 10.4.9 and 10.4.10 that can cause such problem. We have reported this to Apple, but apparently others have found it as well. below is an extract from
www.bresink.de:
Mac OS X versions 10.4.9 and 10.4.10 have serious issues in the component which emulates Carbon file access on top of the underlying Unix system. This can cause problems in all network file systems which don't use the AFP (AppleShare) protocol, including NFS, CIFS/SMB and WebDAV. The following (and other) symptoms can occur:
The Finder and the Open/Save panels may display file system objects on a network volume with wrong names.
The Finder and the Open/Save panels may temporarily display file system objects on a network volume which no longer exist. When you click on those objects, they immediately disappear.
Graphical applications which save file system objects to a network volume may report unexpected write errors although the write operation succeeds.
Only applications using the graphical user interface are affected by this problem. Applications which operate at the BSD (Darwin) level are not affected.
Workaround: Restart the network client as soon as possible when such a problem occurs. Consider downgrading to Mac OS X 10.4.8 or better 10.3.8 if possible. We have made Apple aware of this issue and hope they will fix it in future versions of Mac OS X.