vacuum to cleanup transaction wrap around

All,

have a cluster that hit the wrap-around issue.

We are trying to run the backend vacuum as describe in the manual to clear up the problem.

I not sure how I should be interrupting the messages I'm receiving from the vacuum command.

Here is the approach I take so far (note pg 8.1.4 Linux 64bit)

from command line  run postgres dbname

at the backend prompt run vacuum

the console spits out the following repeated many times 

2007-03-23 08:51:00 MDTWARNING:  database "preR14" must be vacuumed within 999134 transactions

2007-03-23 08:51:00 MDTHINT:  To avoid a database shutdown, execute a full-database VACUUM in "preR14".

There are a few databases in this cluster ( about 6)