Seems like the config file got corrupted.
Which version(s) do you currently have installed? (the CLR field (P2) is another version field, not the one I need to know about)
Try this:
- Open up the following folder:
Documents And Settings\<username>\Local Settings\Application Data
- Open the subfolder 'skwas'
- Delete the subfolders in there (they should start with S3D in the name)
- Restart S3D
The above steps will remove a couple of configuration files S3D uses. It will recreate them when restarting the app.
Let me know, you can try another thing if this doesn't work.
PS: No need to reinstall, I'm sure this can be fixed manually.