Need help with installing plugins on MyBB.

[Rondo19]

I've had my MyBB website up for a little over a month now, and it seems to be working fine. I'm really pleased with how it functions. I haven't run into any problems at all with the exception that I can't seem to install plugins through my cPanel that will work properly. I installed MyBB through Softaculous. Specifically, I'm trying to install the "Thank You Like" and "Google SEO" plugins and I keep encountering error messages like this for the "Like" plugin:

"Warning [2] require_once(/global.php) [function.require-once]: failed to open stream: No such file or directory - Line: 28 - File: inc/plugins/thankyoulike.php PHP 5.3.27 (Linux)
File Line Function
/inc/plugins/thankyoulike.php 28 errorHandler->error
/inc/plugins/thankyoulike.php 28 require_once
/admin/modules/config/plugins.php 484 require_once
/admin/index.php 572 require"

I really don't know enough about PHP or script installation to be able to troubleshoot what I'm doing wrong. In fact, I don't really understand what this error message is telling me. I'm not so concerned abut the "SEO" plugin, but I have users who are asking for the "Like" plugin.

Any offers of help or advice would be greatly appreciated.