Admin error after manual update but now site show blank page...

[BuySellAndSwap]

Hi I manually upgraded to v3 but if I go to http://www.stuff4sale.gb.net/oc-admin/ I get this error...

Fatal error: Call to a member function numRows() on a non-object in /home/a9549671/public_html/oc-includes/osclass/model/Admin.php on line 61

I'm using the twitter theme if that makes any difference so then I tried using the index.php?page=upgrade&action=upgrade-funcs but then I realised that's before 2.4... And now I get a blank page at www.stuff4sale.gb.net

Please can you help me fix this please?

Thank you

[InstaladorX]

Hello BuySellAndSwap,

Have you got any solution for this problem?

Fatal error: Call to a member function numRows() on a non-object in...

Thank you.