What i was saying i could not reproduce was your report that none of the pages could be accessed:
"Now the Log In page won't open. It's a blank page. None of the SA registration pages will open. "
looking at the registration page, it is still creating the SecurityAssist_UserID session:
$WA_sessionName = "SecurityAssist_UserID";
you have not made any of the changes that i suggested to make to correct the problem.