Unable to view add, update, view my plugins

Maybe it helps. When trying to add a video usign a plugin which I have used for a while now (Ultimate Video), I get a “wp-includes/capabilities.php”Fatal error message. I would really appreciate some indications on where to go from here.
I find being unable to update or add plugins to be a real big issue for me.

The website, if useful is www. golyfutol.com.

I guess I must apologize with experts, but as I said I am no expert. It actually wasn’t that difficult; although the difficult part is to figure out what the problem is and then what to do.

I’ll just write what I did so maybe other other non-experts benefit from my 2.5 hours lost figuring this out.

1. I went on to edit (in my hosts website manager dashboard, ipower in my case) php.ini. Memory has to be increased. it was 18, I pushed it up to 36, but you can increase it up to 64 (at least in ipower).
2. Then edit wp_config.php by adding the line
define(‘WP_MEMORY_LIMIT’, ’36M’);
And, at least in my case, its working.