Marketpress install error. Wordpress cannot find where it is installed.

Hello,

I recently upgraded to the new version on Marketpress on a new site. However, whenever I attempt to add products or use any of the functions of Marketpress from within the dashboard I am being directed to a page that reads, "There was an issue determining where MarketPress is installed. Please reinstall."

I have deleted Marketpress and reinstalled it. That has not worked. What should be my next step in correcting this error?

Regards,

Phnom