Blank page using EasySocial

I've installed ParaInvite and the associated application for EasySocial. Every Plugin is enabled. I've also activeted application in EasySocial and imported point rules. After this, in the EasySocial user dashboard (profile) appears a link "Invite your friends" (under applications menu). But if I click an empty page appears. Using a different browser I get 500 server error. Can you please help us solve the problem? Thank you.