PLEASE HELP! I cannot play Requiem :(

[MrCompost]

Hey guys. First of all, I literally only just made this account so please let me know if I'm posting this in the wrong place or something.
Anyway, as the title says, I cannot play the Requiem expansion on my new computer. I installed it onto my old one and it worked fine though. When I try to launch it I get an error message saying "Failed to start game (missing executable)." Now, I've had this problem before and been able to fix it easily be simply verifying the integrity of the game cache, but not matter what I do I just can't get the damn thing working. Upon going into the game files, I noticed that there was no .exe for it but there was a .ico. When I checked through the files on my old computer however, it did have one. I've tried transferring it over to my new computer but for some reason nothing seems to let me. Please help me out here, I've been really looking forward to playing the expansion having loved Overture and Black Plague. Oh, and I purchased it as a collection on Steam about a month ago. Thanks!