Do you have other rmb files in the harddisk? if so, try to play one of them to see whether the Realplayer has problem to play it. If it can play it, then it suggest that the problem is just limited to one rmb movie. If the Realplayer can not play any other rmb movie from your harddisk, then something is wrong with the Realplayer. You can uninstall it and then re-install it to see whether you can fix the problem.