RWW doesn't use the same port as Remote Desktop (TCP 3389); instead the ActiveX component connects to the SBS server on TCP 4125.
If other users are able to connect using RWW I'd say that the necessary port forwarding was already in place - although there is a small chance that the rule is subject to a source address filter to which your IP may need to be added. (I assume you are the person that set up port forwarding?)