I can't provide a quick answer to your first issues.
Regarding restoring the w3t_PollData table, the way to do that depends on exactly what your backup looks like. Do you have a backup file for that specific table, or does your backup file contain all the database tables? If you're not sure, you can examine the backup file (.sql) in a text editor, and see which commands it contains. The commands to look for are:
DROP - deletes database or table
CREATE - creates database or table
INSERT - inserts rows (data) into a table
Which DROP and CREATE commands are in the backup file?
Other information that may be relevant:
Server platform (Windows or Linux)?
MySQL version?
phpMyAdmin version?
