Upgrading to 1.5 error

[jajarom]

I try to auto-upgrade to 1.5 version but after backup succeed, I get an error and I have to import my database again.

I follow the new expert manual to update to the new 1.5 , but when I want to update I get this error :

 

Fatal error: Call to undefined method Tools::getOctets() in /home/dual34/public_html/prestashop/install/init.php on line 72

 

Can somebody help me? Thanks