Added Contact Form 7 Plugin, but users can't use it

Hi:

I'm still new to WPMU running 2.8.4a

I have Supporter plugin installed.

Installed Contact Form 7 and works on the main site.

However, when a user click on Plugins they can see Contact Form 7, click on Activate (and the plugin is activated) but when they click on Settings, they return to the Control Panel index.

As a result, they are unable to set the plugin.

I think it could be caused by an incorrect setting in the Supporter plugin but I couldn't figure it out.

Any clues and what I'm doing wrong?

Thanks.