Word 2003 freezes when opening documents on a mapped network drive

I have a cooworker running a Windows XP SP3 workstation with Office Pro 2003 installed. She is unable to open Word documents on a shared folder on one of our file servers. Microsoft Word locks up and must be manually stopped after several minutes. The document never loads. The odd part of the issue is that she can open excel spreadsheets, pdf files, and txt files within the same network share with no freezing or hanging. She can also open documents on her local machine. This issue appeared this week. The user has been able to access the shared files for a long time prior to this.

The server hosting the files is a Server Standard 2003 box in our domain network. It is NOT a domain controller. Her workstation is joined to the domain, and she is authenticating as a domain user (otherwise she would not be able to see the folder contents, much less open other file types in the network share). All other users that access the drive are able to open word documents normally.

Things I've tried:
1. Uninstall/reinstall of Word component (not full reinstall of entire office package)
2. disabling/uninstalling AV (SEP 12.1)
3. Rebooting system
4. Verified file permissions of network share (kind of a formality, but I'm running out of ideas at this point)
5. Removing the Word documents from the "Disabled Items" list.
6. Opening a test Word document on a different file server (also failed to open).

Any suggestions would be appreciated.

Edit Update: Logging in as a different domain user on that workstation produces the same results.