Unable to validate game version

[Conducting]

I'm a first-timer here. Trying to login and it's giving me an error that reads something like: "unable to validate game version." And also says something about an interference with another program.

What do I do?

I also have Windows 8. Ive already got the realmlist.wtf squared away. Still giving me this error.

[Henhouse]

What version of WoW are you using?

[Conducting]

I'm using the pre-installed version from the website here.

[Henhouse]

I'm using the pre-installed version from the website here.

Is the realmlist by chance .wtf.txt? And is it in the same folder as Wow.exe?