MarketPress Plugin no "Store" tab

I installed marketpress lite last night to test it out and it worked great, however my test wordpress site was being strangely slow. So I deleted all the files from the ftp server and reinstalled them. The problem that I currently have is that I no longer get the Shop tab when I instal MarketPress full version.

Does anyone have a solution so that I can get the MarketPress plugin to work.

Thanks