When the server starts up or when a database is brought online (online database command), the server "recovers" the database by reading the transaction log and applying any committed transactions and rolling back anything that isn't committed.
While doing this the server may have found something nasty in the transaction log - you'll have look in the error log to get some idea of what. Anyway the server couldn't deal with whatever the problem was and you have to do some manual intervention to correct it.
Your options are:
1) Sort the problem out
2) Drop and re-create the database and load from recent dumps
Option 1 is the most preferable, 2 may result in some loss of data, depending on what is being audited in sybsecurity.