How to repair 'could not access status of transaction '

Currently on 7.4.2, I see that 7.4.6 seems to solve the problem. But I need to repair the database. I can survive the loss of a transaction or two. Bottom line is how do I repair the problem.

Actual error message

ERROR:  could not access status of transaction 830358855                      

DETAIL:  could not open file "/var/lib/pgsql/data/pg_clog/0317": No such file or directory                       

The file does not exist.

Thanks,

Lane Rollins        

Boyd Coffee Co.