Wp ECommerce (corrupted) plugin issue

I installed WordPress E-commerce on a large site a while ago. I have since found that there is a problem with processing transactions with Paypal standard payments. The payments to Paypal go through but when I am re-directed back to the WordPress site I get a message saying ‘transaction pending’. Also no emails are sent to either the admin or the customer.

I had large problems with this plugin before when I had traces of an earlier install contradicting the newer one on the database.

I thought I had cleaned the old install completely but I think there are traces left and that is what is causing the issue.

I would like to do a clean install of Wp ecommerce since the site and product database is huge and would take a long time to re-populate from scratch.

Only problem is the corrupted current install I have and getting rid of all the contradictory code in the database.

If this small issue can be resolved using the current setup that would be great also. The plugin is working pretty much 90% correctly, I just don’t know which part is causing the issue.

Any suggestions are most welcome!