There's a reason why they removed the game from the giveaway list. I recommend deleting this ASAP.

Only owners of the game can see this giveaway and thus will not be able to activate the win. This giveaway violates multiple rules and should be deleted.

Read the FAQ and do as the other commentors said; you are new here, so in the simplest terms: if a game is not available in the drop-down menu when making a giveaway for it, 99% of the time it is because it has been given away en masse before elsewhere - such games are removed to prevent abuse of the system. Usually - eventually - these games are made available to be given away (much) later; as for now, it is unable to be given away. As AzureFang said, only those with the game would be able to enter a giveaway for the DLC - if this giveaway IS for the actual game, just adding insult to injury.
If this giveaway ends and you don't send the winner the soundtrack within seven days, you will risk suspension.
Delete this giveaway

Thanks for this giveaway :D

Key is for game yeah! not soundtrack oh well >.<