Hmm, like i said, it was only a guess
I've searched with google and can't find any previous reports of this happening to anyone, on any forum, in any discussions...
Its probably something simple. Have you got the latest version? Maybe its a bug? (though i would have expected it to have been listed)
Usually though, a program will do this if something very important has happened and so it wont let you minimize. I haven't really seen this happen to myself though.
Any ideas? Sorry I couldn't help more.