Sure you don't have another session executing?
Code:
ORA-01153: an incompatible media recovery is active 

Cause: Attempted to start an incompatible media recovery or open resetlogs
       during media recovery or RMAN backup . Media recovery sessions are
       incompatible if they attempt to recover the same data file. 
       Incomplete media recovery or open resetlogs is incompatible with any
       media recovery. Backup or restore by RMAN is incompatible with open 
       resetlogs 

Action: Complete or cancel the other media recovery session or RMAN backup