I'm having problems getting NRPE working with arguments

I downloaded and setup everything and basic things work:

[tt][shinken@server-monitor-1 plugins]$ ./check_nrpe -H server-linux -c check_users
USERS OK - 2 users currently logged in |users=2;5;10;0
[/tt]

But if I try to feed any parameters, it fails:

[tt]
[shinken@server-monitor-1 plugins]$ ./check_nrpe -H server-linux -c check_users -a 1
CHECK_NRPE: Received 0 bytes from daemon. Check the remote server logs for error messages.
[/tt]

To make matters worse, check_disk is just acting weird but it may be based on the parameter problem:

[tt]
[shinken@server-monitor-1 plugins]$ ./check_nrpe -H server-linux -c check_disk
NRPE: Command 'check_disk' not defined
[shinken@server-monitor-1 plugins]$
[/tt]

If I feed it parameters I get the same error

[tt]
[shinken@server-monitor-1 plugins]$ ./check_nrpe -H server-linux.dazsi.net -c check_disk -a -w 10 -c 5 /
CHECK_NRPE: Received 0 bytes from daemon. Check the remote server logs for error messages.
[/tt]

These commands are valid on the remote host (although check_users seems to need parameters, when used remotely it does not? ??? )

[tt]
[shinken@server-linux libexec]$ ./check_disk -w 10 -c 5 /
DISK OK - free space: / 4960 MB (7% inode=94%);| /=57884MB;66197;66202;0;66207
[shinken@server-linux libexec]$ ./check_users


Usage:
check_users -w <users> -c <users>
[shinken@server-linux libexec]$ ./check_users 1
USERS CRITICAL - 2 users currently logged in |users=2;1;-1;0

[/tt]

I really need to be able to monitor disk space remotely.

What am I doing wrong? :-[

== John ==