Very strange... I can't see this happening it here (and so far, you seem to be the only one with this issue). Is your Windows 7 up to date (with all security/other fixes applied) ?
This is perhaps due to an incompatible vcredist package being installed on your system: to check that, you could try and delete (or temporarily move away) the msvcp80.dll/msvcr80.dll and/or msvcp100.dll/msvcr100.dll DLLs from the viewer installation directory and see what happens (try the first couple (move away *100.dll, letting *80.dll in there), then the other (put back *100.dll in, move *80.dll away), then both, and see what happens).
Also, please check that there is no msvcp80.dll/msvcr80.dll/msvcp100.dll/msvcr100.dll in your windows\system32\ directory; if they reside there, then they were badly installed by another application (they should reside in a sub-directory of windows\winsxs\ instead): you should find which application relies on them and move them into that application's directory: just move those DLLs away from windows\system32 (you might have to temporarily disable Windows Protection to do that), and launch all the applications you installed on your system to see which one complains about missing DLLs: once you found the culprit, move the DLLs into its installation directory.
If all the above fails, try installing the
vcredist for VS2010 and Windows 64bits package and see what happens (if the error still shows after that, try again to remove the *100.dll files from the viewer installation directory).