Wrong output in webinterface using check_disk

Hi folks,

i’m new with nagios configuration and struggle with an error in the display of the disk usage in the web interface of nagios2. I want to display the disk sage of the local host (sauron):

The command definition:
define command{
command_name check_disk_gb
command_line /usr/lib/nagios/plugins/check_disk -u GB -w $ARG1$ -c $ARG2$ -p $ARG3$
}

The service definition in the config file:
define service{
host_name sauron
service_description Disk Space 4
check_command check_disk_gb!20%!10%!"/dev/hdc1"
use generic-service
}

The wrong line in the web interface:
Disk Space 4 CRITICAL 2006-11-08 08:26:31 0d 19h 8m 1s 4/4 DISK CRITICAL - free space: /storage/media/video 136298985198123397907742720000 GB (100% inode=105%):

But if I call it from the commandline itself:
sauron:/usr/lib/nagios/plugins# ./check_disk -u GB -w 20% -c 10% -p "/dev/hdc1"
DISK OK - free space: /storage/media/video 127 GB (53% inode=nan%);| /storage/media/video=111GB;190;214;-2147483648;238

Does anyone have an idea how to fix this display error?

Some infos about my linux and nagios version-
sauron:/usr/lib/nagios/plugins# uname -a
Linux sauron 2.6.17-2-k7 #1 SMP Wed Sep 13 17:18:46 UTC 2006 i686 GNU/Linux
sauron:/usr/lib/nagios/plugins# ./check_disk -V
check_disk (nagios-plugins 1.4.3) 1.68
sauron:/usr/lib/nagios/plugins# nagios2 --version
Nagios 2.5
I use the testing branch of Debian, which is called etch.

Thanks in advance,
Impesa

Run the command as user nagios on the command line. What do you get that way?