WordPress MU

I failed to read the error message, so I don't know how helpful anyone can be to this request for help, but here goes anyway.

I uploaded a plugin into the plugins folder and got an error message, and now I can't enable plugins.

Does anyone have a suggestion on where I should start first?

My initial search of these forums didn't reveal the helpful post at:
http://mu.wordpress.org/forums/topic.php?id=6105&page&replies=16