I'm trying to update my install of expressionengine from 2.5.3 to 2.7.3 using DevDemon's Updater module. I installed Updater and then dragged the EE2.7.3 zip into Updater and clicked Start Queue. It then said it was Waiting for a response from the server but didn't do anything. Now when I go to the control panel it just gives me the error
{"error":"
Unable to load the requested class: localize</p>"}
I then deleted the Installer folder which it had created and it went back to normal but it hasn't managed to update EE. What's the next steps to take to work out what's gone wrong?