I got it thx it help t very much.
Had still some trouble with the location of the .pl file.
The verification check was a-ok but i had an error something like "file is missing"
Fist i changed the name of the perl file to check_cisco.pl it looks a bit better.
In the commands.cfg i configured this:
# 'Check_envmon' command definition
command_line /usr/lib/nagios/plugins/check_cisco.pl -H $HOSTADDRESS$ -C public
and in the switch file i configured this..
I Copy d this from a other file...
use generic-service ; Name of service template to use
service_description CISCO Chassis Environment Check
After this it looked ok.
i tested it on the spare switch.
I puled a power suply and after a short wile the errors began to roll.
Thank you very much Strides.