Rdt + outlook + Exchange + office 2007

I am running terminal server 2003 enterprise (RC1 & 2)and exchange 2003 std.
When a Vista client accesses a remote connection and opens their outlook (the
vista client runs office 2007) and tries to make an appointment or save a
task, the system prompts "unknown error". I have followed all traces of this
all the way back to outlook 2000. Un-installing, re-installing, creating new
user profile, detect and repair....To no avail. It works 1 or 2 times and
then reverts back to the "Unknown Error". I have also performed all steps
outlined on / in Microsoft. If I log in (same profile) but on an XP machine
(office 2003, not 2007), no problem!