Networked Computer Cannot Write to Remote Device, but Can Read and Delete

Question

I am troubleshooting a Mac on OS X 10.4.11 that is having troubling file sharing with a file server also running OS X 10.4.11. The computer cannot write to the file server, but can read files, create blank files, and even delete files.
I have a small network that typically includes 5-7 Macs running various versions of OS X and several Windows PCs of various types. All computers on the network have access to a pair of external drives by way of a networked iMac running OS X 10.4.11 with File Sharing and Windows File Sharing enabled.
One of the Macs on the network (also running 10.4.11) is experiencing assorted permissions issues with one user. When attempting to save files to the external drives or file server desktop via AFP, this user account will receive an error to the effect that they do not have sufficient privileges to do so. However, a stub file will be created on the remote machine (an 8K file of the same name and type, but having no content). The user can read files but not save changes. However, they can delete files. Further, this user receives notices that they do not permission to add files to user drop boxes hosted on the same machine.
Interestingly, when connected via AFP to a machine running 10.5.8, this user can read and write files normally.
A new user account was ceated on the affected machine. This accounts functions normally.
Windows File Sharing is enabled on the affected machine, however disabling seems to have no effect.
Permisisons have been repaired via Disk Utility.
Permissions for all files on external drives have been set to 777.
No other devices or users on network are known to have experienced any problems.

Answer 1

Very strange, long shut, but In Finder, select Go menu>Go to Folder, and go to "/volumes".
Volumes is where an alias to your hard drive ("/" at boot) is placed at startup, and where all the "mount points" for auxiliary drives are created for you to access them. This folder is normally hidden from view.
Drives with an extra 1 on the end have a side-effect of mounting a drive with the same name as the system already think exists. Try trashing the duplicates with a 1 or 2 if there are no real files in them, and reboot.