Well, considering Impulse will let you put it on any believable number of computers, I don't know why its giving you issues. I would try manually deleting everything in the SoaSE folder and reinstall it (assuming you've tried the uninstaller already).

I have the same error.  I briefly swapped motherboards due to attempting a motherboard upgrade, but I the new mobo was DOA so I had to RMA it.  I re-installed the old motherboard and the next time I attempted to play Rebellion I got the exact same error as you.

Googling the error online I don't see any mention of it so I don't think it is a common Steam error, I have no idea what is causing it.  Completely deleting the game client and re-installing it doesn't seem to fix it, neither does re-activating it.

Thanks for the response, kryo, I will attempt that this evening and let you know the results.

I did run "sysprep" on my system prior to the planned motherboard upgrade so I had to re-activate windows even after re-installing the original motherboard.  It makes sense that I would have to re-activate other software as well, it's just frustrating to get such an unhelpful error message.

EDIT:  I can confirm that this fixed my problem.  Though the file path kryo listed wasn't exactly accurate for my PC, but I was able to search to find the necessary .bin file.