To remove these entries,
1. Close K2.net 2003 Studio (as it updates this list when it you close it)
2. Click Start, then click Run
3. Type "regedit"
4. Click OK
5. Navigate to the reg key
[HKEY_CURRENT_USERSoftwareSourceCodeK2.net StudioRecent File List]
6. Right click on each entry in the right hand pane and click "Delete"
7. Open K2.net 2003 Studio.
8. The entries have magically disappeared