Photoshop :: CS3 File Naming Error

Photoshop CS3.

The problem is that under a Managed Active Directory Account the software will refuse to automatically add the appropriate file extension to a file. Trying to save a file without MANUALLY inputting the file appropriate file extension will give an error "do you want to overwrite the file .psd?" . The file will then SAVE, but without an extension.

for example...

1) New file created - named "test".

2) File> SAVE... file requester comes up. Type in a name without the extension - "test" and choose the file type (doesnt matter if it is a PSD, JPG, PNG, TIF, but for this argument we will use PSD).

3) Error appears - "Do you want to overwrite file .psd?"

4) click OK

5) file saves as "test".

6) close file

7) File> OPEN... File is not listed. Change Filetype filter to ALL FILES. "test" appears. Note that "test" HAS NO PS ICON!! Select "test".

8) error appears - file is unknown filetype.

9) try OPEN AS. Select file. Select type. File opens.

HOWEVER.... if I name the file MANUALLY, there is no problems either saving or loading.

If you need technical specs
Dual Xeon dualcore, 3.2ghz. Windows XP Sp 2. 2GB ram.
Virusscan 8.5i running.
Computer is on domain.
users logged in with a managed account.