Back end deletion of Buddypress files?

I'm trying to use the Ning to Buddypress importer to move my forums and blogs. The first time was successful but they were accidentally deleted. After a fresh install of Buddypress and import of the information, I was informed that the information already existed, and yet it was not showing up on the website.
I went into the back end and deleted all bp tables from the database following these instructions:
Step 5. Remove the wp_bp_* tables from the database. You can find all of these tables using phpmyadmin and then just check them and click drop. Or you can drop them by running queries similar to this:
DROP TABLE bp_activity_sitewide ;
DROP TABLE bp_activity_user_activity ;
DROP TABLE bp_activity_user_activity_cached ;
DROP TABLE bp_friends ;
DROP TABLE bp_groups ;
…and so on for all the BuddyPress tables.

However, that did not work--after a fresh install and import I am being told those files are still there, and yet not appearing on the site. Any ideas of where they might be so I don't have to completely nuke my entire WP site and start fresh?
Also, I'm having to use BP 1.2.6 in order to do the import, but is there a way for me, after successfully importing the information again, to update to 1.2.9 and still retain the information? Will it automatically do that or will the info be lost (I read about such things and would hate to have to redo it all for the 10th time).
Thanks and I hope I posted this in the correct place. Obviously I'm a beginner here.