Working Good except by modifying “use lib” line.

The command is generating proper output. See below.
cd /usr/local/nagios/libexec/
./check_catalyst_load.pl -s 192.168.1.11 -C nishith007 -w 55,65,75 -c 76,85,85

OK: CPU1000: 2% 2% 2% ! CPU2000: 1% 2% 2% !
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Also, you may need to modify the path where the said plugin has been deployed. In my case, the path is “/usr/local/nagios/libexec/” only.

So, change the path like,
use lib “/usr/local/nagios/libexec/”;