vBulletin Transfer - Headers and client library minor version mismatch

Hi,
I've transferred a big vBulletin forum, i have copied the database and the files..
I have modified the credentials to access at the database but I receive an error..
How to solve?

Line 311:

Code:

if (function_exists('catch_db_error'))
{
set_error_handler('catch_db_error');
}

// catch_db_error will handle exiting, no infinite loop here
do
{
--->>>    $link = $this->functions[$usepconnect ? 'pconnect' : 'connect']("$servername:$port", $username, $password);
}
while ($link == false AND $this->reporterror);