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this issue not related with jomsocial. but I willin to help you, seem you tou wrong code or something.
could you please elaborate more? are you using custom type module?
I can see the ads at your site, and I cannot find UNDEFINED ERROR issue:
I'm talking about the My Google Ads App of Jomsocial.
You can find it between plugins (not module). It's disabled becuse it gives "undefined error".
This app, I think, is for users.
the issue only happening at your site. because you put redirect for domain.com/index.php to domain.com
please remove that redirect code, from htaccess or at server configuration. (not sure where you put it)