prosite not redirecting

installation of prosite plugin created a page http://mysite.tld/pro-site/, containing upgrade link for blogs which shows various packages for upgradation and a paypal link downstream.
click on paypal button initiate page loading but instead of going to paypal website it come back to prosite page, without any transaction.
please help.

its latest plugin with multisite,buddypress enabled site

followed all instruction for new installation