Is the database getting updated when executing an action and your just
don't see the answer from the server? or will the request never be
You can find that out by looking at the logs/development.log file.
When you changed something in the tables (fieldnames, tablenames etc. )
I recomend to run the ajax scaffold generator again, if your not sure
what needs to be changed - that may fix your errors. Attention on
which files to overwrite.
you can read about the debuging stuff here:
don't know how it's called. ask google.
hope that helps