I get this error.

Unable to add cookies, header already sent.
File: /home/mmorpglo/public_html/Forum/includes/functions.php
Line: 5299

Anyone know how to fix it

Please start your own thread when asking for help.

Disable all your hacks globally and see if that resolves the issue.

I did start my own thread.

Then why are you posting in this thread?

Edit config.php in the includes folder and disable the plugin system.

Add this to the second line in the file and resave it to the server:
define('DISABLE_HOOKS', true);

I had this error yesterday and fixed it by using tools.php :

Update the forum and usergroup cache
Update the options cache from the setting table
Update the bitfields cache from the xml/bitfields

Then finally :
In the AdminCP, go to 'Usergroup' -> 'Usergroup Manager' and click 'Go' to edit any of the usergroups (saving is not necessary, going to the page is all that's required).

I had a string of garbage added to my function.php file. I didn't put it there.