***UPGRADE error*

Hi all

I upgraded from 2.5 to 2.6 and follow the procedure on the /install/upgrade... successful but now Zend optimizer Not Installed and on the /admin: Fatal error: Unable to read 1444 bytes in /home/*******/public_html/admin/index.php on line 0

on 2.5 all was working great until i did the upgrade.

Please help

1.Zend optimiser not proerly installed on your server.
Try to reinstall the Zend optimiser.

2.You need to upload all files in binary mode