Membership plugin not working

Procedure Followed- step by step:
1. This is the url of the blog on which we are testing membership plugin - http://myblogstars.com

2. A fresh wordpress installation with Version 3.1 was carried on the domain.

3. The plugin was downloaded from WPMUDev site, unzipped and ftped in the plugins folder.

4. Membership plugon was then activated on the plugins screen.

5. We started following the instructions given on the WPMUDev website as how to set and install the plugin. Categories we created. (Free, Premium and VIP) Membership levels were created (Free User, Premium), Rules were applied and the levels were activated. Everything went fine untill we reached the Edit Options stage, where we were supposed to give the details of the pages, subscription, membership and shortcodes. When we hit the save changes button a blank screen appears taking infinite time to display anything. Because of this we cannot even ascertain that the settings are properly saved.
6. When we check on the front end, the rules and content access are not working.

Additional Info: We are running it on IIS environment.