[Scanu]

This is because in vb4 you can't use fetch_template to use a template you must use oop. Here's a great article about this: https://vborg.vbsupport.ru/showthread.php?t=228078
Btw Try this code

PHP Code:

$templater = vB_Template::create('my_bar');
      $vbulletin->templatecache['header'] = str_replace('<div class="above_body">',$templater->render,$vbulletin->templatecache['header']); 


And about this error

Warning: array_merge() [function.array-merge]: Argument #1 is not an array in [path]/includes/class_bootstrap.php(1419) : eval()'d code on line 3

Can you show me the code you usef to cache templates?