There are a couple of things you should try.
1. Duplicate your Band-in-a-Box/Preferences folder to save a backup of it, then delete the contents of Preferences.
2. Try running Band-in-a-Box.
3. Close and then try to open it again. Does it open the second time?
4. If not, delete the Preferences again and open. When the program is running, go to the Plugins window, and check to see what third party plugins you have (i.e. other than Apple plugins). Try adding them to the exclude list, and then try running Band-in-a-Box again. Please let us know the details of what you find.
PG Music Inc.