Hey Ad,
Apparently for some reason, the code doing this check is not getting the actual version number. Which implies the problem lies elsewhere and this is just the first thing that is blowing up. My guess is that there is something wrong with when your extensions are getting loaded. I don't quite remember the details, though suggest that you look at the installation instructions of the relevant extensions for MediaWiki 1.24, and make sure you are doing what is outlined there, and no additional (outdated) things.
it must be 1.16 or higher
I just realized that the current constraint is 1.17, so perhaps you are simply running a too old version of the extension?
Cheers
-- Jeroen De Dauw - http://www.bn2vs.com Software craftsmanship advocate Developer at Wikimedia Germany ~=[,,_,,]:3