Probabaly from trying to force it into gear as I noted earlier in this thread. (ie: trying to slam it into gear w/ the clutch still engaged)

People are telling people to put JB Weld on the clips to keep it in place, don't do this!!! How the clips work is that they need to be curved (bent) a little bit so that the bend comes out about to where that little top part pokes out to, and then the legs of the clip back, not to much or you won't be able to get it back on.

If it's tight enough you will need a hammer to tap it into place.