ImportError: No module named json

Hello, I try to use your plugin in a FAN version of NAGIOS (core 3.4.4). But when trying to execute your script I have the followinf errors:
ImportError: No module named json
and
Unable to login to VCSA API, please check credentials and firewall.

Is my problem due that JSON is missing in FAN, if so is it possible to install that module or not, or do I have to install a new version of NAGIOS with JSON embeded ?

Thanks for the answer.