Hello Franky,
it may well be a qtranslate problem, but it only appears in “Events made easy”, not in the regular WordPress items. So I haven’t seen this warning appear. My WordPress is 3.5.1 and my qTranslate is 2.5.34.
qTranslate.php mentions WordPress 3.5.1 as supported version.
And like I mentioned: I had the same problem with WordPress 3.3.1 en qTranslate 2.5.24 after updating to EME 1.0.9 (from 1.0.4).
After downgrading EME back to 1.0.4 the problem is gone.
I will try to figure out what might cause the problem, but right now I don’t have time for that.
Any suggestions?