I am trying to log in but a fatal error appears:

Fatal error: require_once() [function.require]: Failed opening required '/home/circusho/public_html/aerialedge.co.uk/jupgrade/components/com_acajoom/defines.php' (include_path='.:/usr/lib/php:/usr/local/lib/php') in /home/circusho/public_html/aerialedge.co.uk/jupgrade/components/com_comprofiler/plugin/user/plug_acajoomcbplugin/acajoom_cb.php on line 14

We just upgraded our Joomla site from joomla1 to joomla 2.5 using jUpgrade...

I definitely have no idea why this happens? can anybody out there help me? please?