See if this helps:
http://support.microsoft.com/default.aspx?scid=kb;en-us;304498
If none of those helps, credit goes to Peter Foldes for this fix, which
several people say has resolved the issue:
1st Rename Office subkeys
Note: Removing the following registry keys may reset customized user
settings for your Microsoft Office programs.
1. Close all the applications.
2. Click on Start->Run, type in REGEDIT and click on OK.
3. Locate and select the following registry subkeys:
HKEY_CURRENT_USER\Software\Microsoft\Office\11.0
HKEY_LOCAL_MACHINE\Software\Microsoft\Office\11.0
4. Right click on 11.0 and rename them to Old11.
5. Close the Registry Editor.
2nd. Detect and Repair Office 2003
1. On the Windows taskbar, click Start, point to and click Control Panel.
2. Double-click Add/Remove Programs.
3. Click Change/Remove Programs on the left pane.
4. Highlight Microsoft Office Professional Edition 2003 on the right pane
and click Change.
5. Insert the correct version of CD when it requires.
6. Select "Reinstall and Repair" and click Next.
7. Select "Detect and Repair errors in my Office installation".
8. Click Install and wait the process to end.
3rd. Install the Updates
