Vacuum dooes not respond

Hi,
I am doing a "Vaccum verbose analyze;" on the database. The first time
I did the vacuum it stucked at a table and I canceled it ctrl z. Then I
deleted the file pg_Vlock and I tried to do it again, but this time it
doesn't do anything. It is just hangs there doing nothing.

I use PostgreSQL 6.5.2.

Thanks