Just download the source code from Github in zip file. These files are currupted since FOREVER.
\Engine\Source\ThirdParty\nvTextureTools\nvTextureTools-2.0.6\src\project\vc8\nvassemble\nvassemble.rc
\Engine\Source\ThirdParty\nvTextureTools\nvTextureTools-2.0.6\src\project\vc8\nvcompress\nvcompress.rc
\Engine\Source\ThirdParty\nvTextureTools\nvTextureTools-2.0.6\src\project\vc8\nvddsinfo\nvddsinfo.rc
\Engine\Source\ThirdParty\nvTextureTools\nvTextureTools-2.0.6\src\project\vc8\nvdecompress\nvdecompress.rc
\Engine\Source\ThirdParty\nvTextureTools\nvTextureTools-2.0.6\src\project\vc8\nvimgdiff\nvimgdiff.rc
\Engine\Source\ThirdParty\nvTextureTools\nvTextureTools-2.0.6\src\project\vc8\nvzoom\nvzoom.rc