I installed a 3Com 3CREB96B USB Bluetooth dongle using the latest XP drivers and
Bluetooth Connection Manager [BTCM] available from 3Com's site. If logged on via an
account which is a member of the "Administrators" group, all appears OK and BTCM
(COM ports view) shows all the ports. However if logged on as a member of the
"Power Users" group, BTCM does not show the COM ports, the panel appears entirely
blank, as if BTCM cannot access the registry perhaps; maybe some kinds of "permissions"
issue. (BTCM does show the remote BT device in range etc.) The result is that any
"Power User" [or “User”] attempting to use the BT DUN device finds that it dials and fails
to make a connection without ever attempting to actually connect to the BT DUN device
I reported this issue to 3Com and received the following reply from eSupport@3com.com:
“…
The driver for 3CREB96B has been designed as only worked for "administrators" group.
Therefore, the symptom you mentioned in SR(service request) is NOT abnormal behaviour
.…”

Designed?

I note Graham Wharton has provided an article on how to avoid using 3Com’s BTCM http://www.geekzone.co.nz/forums.asp?ForumId=8&TopicId=3452