I had the same problem. Here are two possible solutions that worked for me.
One: Move the file you want to register to the bottom of the other files, making it the last one that registers. This is typically because the file you are trying to register is dependant on other file being there or already being registered.
Two: If that fails, then remove the "Allow xxxx to self register this file." from the checkbox in the "properties" section of the file.
One (or both) of these should work.