exchange monitoring :Error # access denied

hi i have downloaded a copy of manageEngine application manager 6.

was working on evaluating this for monitoring exchange 2003 server. it was working kind of okay. but for the last 6 hours it have been giving a message

error # access denied.

when i go to monitors > exchange server > server name.

and it does not show any stats!

i had deleted and recreated the monitor's but no help. when i add a monitor it goes through okay, but when i go the monitor screen it shows me this error.

i know this seems to be basic beginners issue. (i am a beginner in this one)

any clue as to the problem?

paul

p.s: i did search the forum for the error message. :)