Authentication problem

I have a client authentication problem I need help with.

I have the postgresql.conf listen_addresses='*'

and in pg_hba.conf I have
host VRNJED all 2.30.0.0 255.255.0.0 md5
(I've also tried the following with the same results)
host VRNJED all 2.30.0.0 255.255.0.0 password

I have three clients on Windows PCs each on a different subnet (2.30.50,
2.30.190, 2.30.31). One of them connects just fine, the password is asked
for and the logon succeeds, but the other two get

C:\dev\PostgreSQL>psql -h robux -d VRNJED -U vrngui
psql: FATAL: password authentication failed for user "vrngui"

I'm not sure why these two fail when the others work. I also have another
linux server on a completely different network that is also able to connect
just fine. Is there possibly a client configuration file I need to have the
users check something in?

Any help would be greatly appreciated.

Thanks,

Jed S. Walker