Error showing on redirect after sending PM

[pjkcards]

After sending a PM, on the redirect at the top I get:
Warning: Only variables should be passed by reference in ..../private.php on line 767

Warning: Cannot modify header information - headers already sent by (output started at ..../includes/class_core.php:5755) in ..../private.php on line 926

It doesn't seem to cause an issues, but I want to resolve it. Where should I start? Thanks.

[ForceHSS]

test it on default style

[ozzy47]

Also try with all mods disabled.

Open your includes/config.php file and below

PHP Code:

 define('DISABLE_HOOKS', true); 


So it looks like this:

PHP Code:

 <?php
define('DISABLE_HOOKS', true);
/*=================================================  =====================*\
|| ##################################################  ################## ||
|| # vBulletin 4.2.2

Then see if the issue still persists.