Volume dosn't check in as Scratch

Hi all,
There 2 volumes in my library that arn't changing to scratch when I issue Checkin command. I'm not even sure how to trouble shoot this problem... but let me tell something I do to usually fix this problem.. whenever this kind of problems happen to me I just change the place of the tape to another slot.. and checkin again.. untill it is changed to scratch.. but I want to know the recomanded solution.. or what should I do.. please help :(

EDIT: I managed to solve the problem. Thanks.