For Zend encoded files, you may face following error
Fatal error: Unable to read 32654 bytes in
/home/xxx/public_html/includes/functions.PHP on line 0
Its most probable the related files for the script are uploaded in ASCII mode,
all encoded files must be uploaded in binary mode.
01. You need to reupload all files in binary mode,
or set the transfer mode to auto in FTP client.
02. Check if short_open_tags in set as On in PHP configuration ie php.ini
03. Check if you have updated versions for Zend optimizer or ionCube loaders.
In most cases, files reupload in binary mode resoves the issue.