If you're trying to install Gametap I assume you've already downloaded it. If you've got another program like Spybot or Malwarebytes - there are others - on your system you can probably do a scan of the download with a right-click of your mouse and selecting the appropriate option.
If McAfee is finding a Trojan in the download you have to accept that you may indeed have an infected file.
I've Googled for Gametap downloads and I see that you can get it from CNET. If it's a free download I suggest deleting the one you've got and getting another from CNET - they guarantee that their downloads are malware-free so if there's still a problem you can go back to them and ask them to double-check and run their own tests with some other AV software.
Best I can advise but I see you've been asking about this for a while and no-one's been much help.