media portal mod on dolphin V6.1.4

hi all ,
i installed the media portal mod , the mod which give categories for the movie , music and pics,
all went well , but , i had some media before, and when i signed in as a member , i have the My videos and under it listed all the videos i have , and under each video is the drop down menu to choose category for the video , after i choose the category , and click change , i get a blank page or http 500 internal error , and the video doesnot add to the catagory ,
see pic attached to know what i mean , regarding adding to the category ,

any assisstance will be greatly appreciated , zaq