Same Problem here, any solution for this?
I'm not sure since it's been a long time since I've touched IPA, but it's possible the game did not come patched already.
Drag the main game.exe over IPA.exe, which will create a new exe which should say something like, "game (patch & launch)".
If the game folder already has a patch launcher, delete it and start over, this may fix the plugin.
Run the patch once and the plugin should work.
Otherwise (if that doesn't work) I'm not sure, if my memory serves me well, I think the translator for this game was bugged at some point because people were sharing incompatible versions.
There is most definitely a hongfire thread which hosts the same plugin, and you may need to simply redownload the plugin.