PM alert box(tech question)

[NobodyToYou]

Hey,
Not sure whether this is a BUS problem or something wrong with my computer. The little alert box has been popping up a lot today but when I check my messages there is nothing new there. I know someone once said that it could happen if someone deleted a pm before it got to you....but this is happening way too often for that, just about everytime I change screens.
Not sure if this is relevant, but it could be...My computer is using Linux, not a Microsoft operating system. So...that might change some things or might not. I don't know.
If you know what I should do to make it stop, please let me know.