You should run a DBCC CHECKDB as soon as possible.  SQL Server is often times able to recover using one of the repair parameters (REPAIR_ALLOW_DATA_LOSS, REPAIR_FAST, REPAIR_REBUILD) for CHECKDB.  The results of DBCC CHECKDB will tell you more about the problem and offer suggestions.  This is often times caused by some sort of controller caching problem.  If you continue to experience this error and have caching on your controller enabled, you may try to disable it and see if your problem goes away.  Also, check with your controller vendor and see if you have the latest firmware and if they are aware of any problems.