What can you do when you are playing Black White and an error message comes up saying something is wrong with runblackexe?

Well, one thing to try is to look online for a patch. Sometimes the game's website (or the website of the manufacturer or distributor of the game... whatever company is listed on the box) will have information about known bugs, and will have patch files that you can download to fix the game. Another thing that you can try if that doesn't work is reinstalling the game. Completely uninstall it from your computer, and then reinstall it using the original CD or disks. If you can't find any information online, and reinstallling doesn't work, try to contact the company through their regular "support" or "help" email address... or phone number. Hopefully, someone will know something. :)