This normally fixes PayPal issues. Give it a try.

First, copy down all of your PayPal settings and info for the module that you want to use.

Second, remove all of the PayPal Payment modules by going to Admin, Modules, Payment, highlight each PayPal module one at a time and click remove for each one so that they are all removed from use and show a red circle.
Then, lastly, click the line of the module that you DO want and click install to add that module back in. Then edit the module and put your settings back in place for your particular account.

That should remedy your problem. Test it out and make sure everything works like it should.