I'm guessing you skipped a part of the howto
Please review this:
Now we define "server1" as the primary/master server:
drbdsetup /dev/drbd0 primary --do-what-I-say
Wait a while to have the "ext3" filesystem created on /dev/drbd0 and then:
drbdadm connect all
If you don't get errors, you should be able to continue the howto (e.g. mount the /var/vm etc ...). If you do get errors using any of these commands, please post it here !