there are some things that Nortel told me have to happen for RCC to work:
1) the RCC server can't be running google tool bar, mysearch, a firewall, or virus protection. (particularly McAffee)
2) it must have Java runtime 1.4.2, not an upgraded ver. of Java.
3) it may not be cp 3.00.25.xx - 3.00.27.xx (nortel says that version is "broken")
now, this may or may not be true, but untill I made the machine I was installing on compliant, I couldn't synch up w/ the cp
i don't know if any of this is relevant to your problem, but you might want to check it 'cause in the words of Nortel, these things make RCC "flaky."