It's weird and scary - in a perfectly functioning Joomla site I installed one of my favourite components, Joom!Fish - remember, I'm the multilang guy 
- and all I got was a blank screen. Obviously, something gone south... but what?
Firefox don't showed me anything usable, Chrome was the one to sow me the first clue: a 500 server error. Obviously Joom!Fish tried to access something forbidden by the server settings.
What to do next? Take a look to the error_log, obviously, and here I found the first clue:
PHP Fatal error: Class 'DOMDocument' not found in /***/administrator/components/com_joomfish/models/cpanel.php on line 130
Humm, what a heck is this... Obviously, the next step was to search the Joom!Fish forums. I found a lot of bullshit, and another clue:
What a heck... I just installed the latest CentOS with all the bells and whistles... who to ask? I asked myself already... 
Uff... but let's make long story short, finally, in some other forum I found this:
and then this:
Bingo! Mission accomplished.
