The problem here is what the definition is of a "Potentially Unwanted Program" and a "Trojan". More information about a PUP can be found here. Or check this article: What are viruses, worms, and Trojan horses?
If the scan doesn't warn you about any trojans, then I wouldn't worry about it. Did the previous report show you that it has cleaned the trojan? Did it give you a name of the trojan?
The "Stinger" program only scans for a certain number of viruses and not all, which is actually impossible.
You can always do an online scan, like the one here. But if you do this then I'd disable the McAfee scanner first. Running two scanners on one computer is not a good idea. They'll bite each other.