Media browser question

When I try and navigate out of the normal, pre-configured media areas like "Audio Library, Midi clips or Project files" from the drop down menu in the media browser, say to my desk top or somewhere else within my file structure, I get an error message which reads,"This Parameter is Incorrect." It's not a consistent error though, like when I detach the browser from the side dock, it lets me go where ever I want. Any thoughts?