(1) Go back and read Post #10 in this thread. Then go into phpMyAdmin and see what your phpdig database name is. If your database name looks something like this:
your database name has a prefix. That prefix is whatever precedes the underscore. The database name is what follows the underscore. So what database name do you see?
(2) Are there any table definitions associated with that database? If not, run init_db.sql again, just like I told you previously.
If you still have problems, post back with answers to the above questions, and we'll go from there.