When activating the FALANG plugin, the following error messages occur when starting the WEB-Site:

Warning: include_once(/var/www/vhosts/rolleropen.lu/mychoiceintown.com/plugins/system/jfdatabase/intercept.jfalangdatabase.php): failed to open stream: No such file or directory in /var/www/vhosts/rolleropen.lu/mychoiceintown.com/plugins/system/jfdatabase/jfdatabase_inherit.php on line 51 Warning: include_once(): Failed opening '/var/www/vhosts/rolleropen.lu/mychoiceintown.com/plugins/system/jfdatabase/intercept.jfalangdatabase.php' for inclusion (include_path='.:') in /var/www/vhosts/rolleropen.lu/mychoiceintown.com/plugins/system/jfdatabase/jfdatabase_inherit.php on line 51 Fatal error: Class 'interceptDB' not found in /var/www/vhosts/rolleropen.lu/mychoiceintown.com/plugins/system/jfdatabase/jfdatabase_inherit.php on line 52

I had the same issue and resolved it by manually changing the code in
plugins/system/jfdatabase/jfdatabase_inherit.php
Line 51: change
include_once(dirname(__FILE__)."/intercept.".strtolower(get_class(JFactory::getDBO())).".php");
for
include_once(dirname(__FILE__)."/intercept.jdatabasemysqli.php");

For you it might be
include_once(dirname(__FILE__)."/intercept.jdatabasemysql.php");
if you're using SQL instead of SQLI

DO A BACKUP before trying it.
I had an issue afterwards. The FaLang database wasn't loading, but it was due to the fact that I had JoomFish installed and enabled. Once I disabled it, everything worked fine.

Good luck!

Oh, also, you have to disable SEF URLs
Go to Global Configuration. In SEO Settings, set "Search Engine Friendly URLs" to No

Thanks for the information. I currently try with Joomla 30; apparently with this Joomla Version there is not need for Joomfish or Falang anymore. However, I could not yet find out how it works.