From what I can gather from a quick Google search, Steam likes to revert to the old version of POL when it updates or something. You can download the right version from SEs website if I'm not mistaken and re-install it. It might be a bit annoying with steam, and you may have to do something like: install the newer version to your PC, rename the POL folder in Steam's folders to something else (I usually just add (backup) to the end of the file name), and then cut/paste the newly installed POL folder into Steam's directory... or it could be a lot simpler, not sure, I don't play using Steam. Have you tried a POL file check first?
Edited, Feb 24th 2013 1:02am by Diamondis
See You Space Cowboy