I'm only guessing that you might be using Win 98. I've always had problem with the Real Player either locking up or hogging system resources. I've spoken to one of the developers of RealPlayer and they're very careful what thry tell you - one thing he did mention was the word "problem" the preceeding word was "possible". I translate that as "full of bugs".
The only thing I can suggest is that you note the full error and e-mail Real Player support and see what they say.
Buttons