When I try to play Ravenskye City I get a "501 error" message. This is the only Facebook game where this is happening.
How can I solve this error?
The error you have is related to a file that is used by Adobe Flash Player. My suggestion is that you try and clear the stored files and content used by this necessary plug-in. As it was updated over time, the Flash Player is available for customizing from the Control Panel. Start the application and clear the content stored on your computer and besides that, this error is often used by Chrome browsers. The file which is responsible for this error is pepperflash.dll. If it is still not working after taking these steps then you should install Adobe Flash Player ActiveX package for Internet Explorer and then try and run the game again.
