Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to allocate 36560 bytes) in xenforo/library/XenForo/Image/Gd.php on line 56
php_value memory_limit -1
I think, that allocating 134Mb of memory is a little bit HUGE requirement. Almost every hoster will kill you for such a resource waste.Make sure debug mode is off. Remove the debug line from the library/config.php file if you previously added it.
If you still get the error then you need to ask your host to increase or disable PHP's memory_limit.
You can also try changing the memory_limit yourself. These methods don't always work, but try adding this to your library/config.php file