paycollect.tt has (for a long time) contained a onsubmit reference which refers to a function that has never existed. It causes noise in browser debuggers but no other side effects. Should be removed ideally. <form name="payindivfine" id="payindivfine" onsubmit="return validatePayment(this);" method="post" action="/cgi-bin/koha/members/paycollect.pl"> 2 occurrences of the above in this file.
*** Bug 16135 has been marked as a duplicate of this bug. ***
This seems to have been fixed.