How are you backing up and restoring your database? Are you backing up to tape, disk or using a tool like Tivoli TSM? Note: if you are restoring and missing log files it will fail.
For TSM:
db2adutl query
db2adutl verify full taken at {timestamp}
For Normal DB2:
db2ckrst
db2ckbkp
If you provide us with more details perhaps I can help you out more.
Scott