This is a good hint, actually. I did exactly that, when transferring the plugin-VIs from my desktop pc to my laptop. As I have both LV2011 and LV2013 (x86 AND x64) installed, I became a bit messed up with which VIs to put where. Somewhere in the middle of the process I realised I had accidentally put the 2013-VIs in the 2011 folders. So this is what will definitely have caused the observed behaviour.
Since the laptop is somehow messed up with our network domain anyway, I think I will go for a complete system reinstall at any rate. And now I am forwarned 
Thanks again for the insight, Darren.