Can’t use Perf. Monitor from workstation

We have a two domain NT 4.0 structure (DomA and DomB). There is a one way trust between DomA & DomB where DomA can access all of DomB. We are trying to run performance Monitor from DomB on servers in DomA. We are unable to do this at this time.However this scenario has been accomplished before by another person who has since left the company. We have also tried the run as feature of Win2K with no success. How can we make Perf Mon work with our current setup?