Some of the programs are just looking for names in the registry (such as Wild Tangent), and when they see something called that, make the assumption that it is malicious. These could be empty keys, or keys that point to non existent files. Meaning, there is no risk.
Registry Scanners. Sure. Tons of them. A dime a dozen. Trust any of them? Few people do. Regardless, having dangling references in the registry is nothing to be concerned about.
But, if you wish a second look for Wild Tangent (which I doubt is there if the 3 apps above didn't find it), you can download, install and run
HiJackThis
Run the Scan and save log file option
When the LOG file opens in NotePad, Select All, Copy
Then, return here and in a reply post, Paste.
Someone can then review and confirm that your PC doesn't have WT installed.