I'm upgrading/migrating my website.
-Have upgrated from the old 1.5.15 to 1.5.26
- have installed Jupgrade
- have upgrated using jupgrade to 2.5
and was able to login w/o problem to back end
then Jupgrade asked to upgrade to 2.5.4
which I did
Only then was I taken through the 6 or so steps of installation
(creation of website w/ joomla, msql login etc)
When finished, successfully deleted "Installation" files
Now:
I can no longer login to back-end and get this message:
I have tried, as seen on other topics, copying original controller.php file... doesn't change anything.Fatal error: Call to undefined method JSession::checkToken() in /homez.46/roulevog/www/jupgrade/administrator/components/com_login/controller.php on line 52
and I have no idea either of what the error means or how to fix it... obviously

Thanks in advance for any help