The message is “The Adobe Flash plugin has crashed. Send crash report” and the screen goes gray, with FarmVille not loading. If you’re having this problem, then you’re certainly annoyed, but we’re going to try and help you fix it right away!
According to the official forums, the problem can be solved with the help of Mozilla themselves who are telling you what to do in order to fix the Adobe Flash player crash problem:
“By default, if Flash is not responsive for 45 seconds, Firefox will terminate it and display The Adobe Flash plugin has crashed. However, some Flash-based games such as FarmVille and Mafia Wars can take more time than to load, unnecessarily triggering this hang protection. This is especially true on slower computers or if you’re running intensive Flash apps in many tabs or windows at once.”
Basically, since a better computer or internet connection are probably out of question you can fix the Adobe Flash Player crash by upgrading Mozilla to the latest version and also upgrading the flash player to the later version. Also, Mozilla explains how to Disable hang protection here, something you should try only if the crashes become very annoying!