Hi,
Glad its working! I have found myself that File Manager is broken under medium trust if the hosted environment is IIS7 (ie. windows vista) but works for me in IIS6 on Win 2003 as long as NeatUpload is disabled.
Might be related to the unfixed bug in IIS7 noted here:
http://www.brettle.com/neatupload
If you want to vote for MS to fix it, visit here:
https://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=308352
Best,
Joe