[Sew_Sumi]

More than likely you haven't got the runtimes required (Usually on a clean install system this will happen) or if you have updated the plugin recently, you should try reuploading it as it could be corrupt in the transfer, either from downloading it to your computer or uploading it to the server.

Should say what OS you are on, and whose plugin it is. Along with what you've done in the leadup to this.