Ok, a little bit of research leads me to suggest the following ...
1. Ensure you have the latest version and try re-installing it
2. Try running it as Administrator
3. Make sure there is a .titanium folder in the user directory - there should be a config.json file in there
4. Try changing the default Workspace under Preferences\Startup and Shutdown\Workspaces
Failing that there are other items
on the Q&A [
^] at appaccelerator - which is the best place to ask further questions