Hi,
did you execute the checkpoint in the database in question?
A full backup does not truncate the transaction log.
You should try a transaction log dump as well. In the following examples the log is truncated; subsequent tranaction log dumps to a file will not be possible. A full dump must be done first. So execute:
dump tran <dbname> with truncate_only
or (if the transaction log is "too" full):
dump tran <dbname> with no_log
Best regards,
Juergen