Problem loading modules in back office (error code in message)

[malicious m]

i upgraded to the new version of prestashop but had lots of problems so reverted back to my back up to previous version but now i cannot view any modules in the back office i just keep getting this error

Fatal error: Class 'CarrierModule' not found in /home/madacs/public_html/djmusicfinder/classes/Module.php(323) : eval()'d code on line 29

can anyone help me as its really getting my back up now as to why it wont load
i have tried increasing php memory by changing php.ini to 128m but stilll not loading

many thanks in advance for ANY help

Mark.