We have recently upgraded several Nortel 8600's to code 184.108.40.206 and the Switch Port Mapper tool no longer populates the 10/100 ports. The only ports displayed are gig uplinks and ATM connections. SolarWinds Customer Support seems to be stumped, so I'm hoping someone out there can shed some light on the problem.
I suggest you perform and complete MIB walk on a Nortel switch before and after the upgrade and send the information to SolarWinds support. From this information, they should be able to tell you what happened.