Supporter & Upgrades not working automatically

I have both Supporter and Upgrades installed on my site at http://kbkconnect.com. It is a multisite.

These plugins are allowing purchases/subscriptions, but not applying the information to the users' accounts. For instance, a user/admin purchased credits for an upgrade. The PayPal payment went through, but their account was not credited with the credits. I can manually add credits to accounts.

Another example is that users can subscribe to Supporter, payment goes through PayPal, but the subscription is not applied to their account. Again, I can manually extend accounts.

All tables are created in the database. IPN is turned on in PayPal.

This is getting hairy as more people use my service. Help!!!