I am using Membership pro and it worked fine

Hi,

I am using Membership pro and it worked fine on a development plattform. Now I wanted to install it on the final URL; but once I hit "Activate" in the dashboard I am getting the fatal white dashboard.

As soon as I am renaming the folder via FTP everything is back fine. I am using nothing that I haven't used before. Where is the conflict? Need urgent help!

Marian