R hangs when I run 'rmSessions()'

Dear all, I am having a strange problem with doSMP package. When I start a fresh R console and run 'workers <- startWorkers(2)' I come up a warning message: there is an existing doSMP session using doSMP1?

Why I should get that message as I start a fresh work into R?

Next when I try to?disable?that with rmSessions("doSMP1"), R hangs.

Can?somebody?share any such similar problem? How you then resolved it? If I do not run?rmSessions("doSMP1") at all then would I get any problem? Can I still utilize my dual core for my calculation? I am using windows vista with latest R 2.13.1

Thanks for your help