I had this issue with IM on my old host and some where along the line SD jumped in about execute permissions and then Rick jumped in and got it resolved.
So anyway. I know I have a post here in the last year about it and sd replied.
But I spelled out the name image magic or what ever.
Let me see if I can find it.

Not much of a answer but here is the topic.
www.ubbcentral.com/forums/ubbthreads.php/ubb/showflat/Number/247204/
Also to test it here is a post by Rick:
Quote
While logged in as an admin user, bring up the following on your forums:

ubbthreads.php?ubb=captcha&t=im&test=1


Blue Man Group
There is no such thing as stupid questions. Just stupid answers