Hello, the first suggestion would be to make sure your iDRAC6 firmware is up to date to address any known bugs. As of 1/11/2011, the current version is 1.4.0.586

There is also an existing threads on Dell TechCenter that might help you out - does this sound like the same issue?
http://www.delltechcenter.com/thread/4293040/iDRAC6+error