It's weird that one app would affect other apps since usually they are pretty insulated from each other.
Deleting .table files can be a problem. Was the app under development and you wouldn't care if you erased the DB? If so (and it's SQLite), you can delete all the files in the "database" directory and start with a fresh new DB. When you say that it's not working, how exactly does it behave? Do you get any error messages? Have you touched the routes.py file? Another thing to consider is downloading a fresh version of Web2py and then copying the applications over one-by-one.
