Block Spammer Domain

[Tripple]

In an effort to block all spam from firstmail.com, which is floating my mailqueue on a Debian ISPconfig server I tried this:
http://madphilosopher.ca/2006/09/how-to-send-an-entire-domain-to-dev-null-in-postfix/

This didn't work. No one could receive any mail anymore on that server. Then I deleted all changes, reload Postfix but now I find this in my log:

postfix/trivial-rewrite[3387]: warning: database /etc/postfix/virtusertable.db is older than source file /etc/postfix/virtusertable
postfix/cleanup[3388]: warning: database /etc/postfix/virtusertable.db is older than source file /etc/postfix/virtusertable

How can I fix this and what did I do wrong?

thx.

[topdog]

Run this command

postmap /etc/postfix/virtusertable

[Tripple]

Thanks.
I still wonder why it didn't work.