seems by accident you may have clicked on the exe (game shortcut) twice, as that's the error reported, glad you're sorted.
most problems with this error are but not all are, antivirus program or background apps, or a combo of both, first try get caught letting second one go through, then game kicks it out as it thinks that it's already running it, and it won't let 2 processes run at the same time and comes back with the given message.
best to try a clean gaming profile, one with as little as possible running in it,
second add the game exe to any antivirus and other program installed on the pc, popup blocker, spyware app / program etc.
Google how to add exception to antivirus and instead of anti virus add your anti virus name in there as well, it will show you a how to on their web site, or should if it's a half descent one...
3rd, when a error happens, try event viewer and also look at task manager to see what or how many processes are running and see if any are dupes, the only one that normal has more than one in there is browsers like chrome.
4th final one, it's steam error, best bet is to try steam forum and support, as code given with error normal has a given page to visit for extra information, and most of the time we wont or might not know the code number, but can search for it if given or known for a answer to steam codes or steam errors.
5, thread does give another correct answer as well
5, event viewer guide
again sorry for your troubles and good luck with the game, i haven't got the game either, just do general help when on
< Message edited by zakblood -- 12/3/2015 8:59:45 PM >