First off, BCC does fail to load on occassion on Nortel routers. Just try it a few times. If it fails more than 3 or 4 times in a row though, then you probably do not have neough free memory. Rebooting the router will generally allow you to get into it if that is the case though.
Regardless, once you are into BCC, type the following:
config
ethernet 1/1
ip address 10.10.10.10/255.255.255.0
Of course, use your IP info instead of that listed above. Do not be confused by the "E12" name. That IS your Ethernet interface as it is displayed in the Technician Interface via a command such as: show ip circuit