Error 9002 lead to a shutdown of db

Hello,

My database shutdown due to error 9002, instead of get in the read-only mode.

The error message is :

04/12/2013 16:34:15,spid169,Unknown,Database BizTalkMsgBoxDb was        
shutdown due to error 9002 in routine 'XdesRMReadWrite::RollbackToLsn'.
Restart for non-snapshot databases will be attempted after all          
connections to the database are aborted.    

We are looking for what could cause this shutdown ?

Any clue ?

Thanks for you help. Regards. Etienne.