hub

Okay, so I went to replace my chain and sprockets this weekend. Chain comes off fine, replaced the front sprocket fine. But when I went to pull off the rear sprocket, I found that five of the six nuts just spin around the bolts. Watching carefully confirms that the nuts are spinning, but the...

Hopefully the picture attachment has worked...... I was cleaning the rear wheel of my newly acquired FZ6S and I discovered this mark on the hub, i'm fairly certain it is a score and not a crack but I just wanted to find out if there were any reported issues of cracked wheels just in case.