The latest version of Pro Tools First is not qualified to run on Windows 7.
I would never suggest downloading a single dll file from the internet as most of these sites are not reputable and you are really taking your chances.
The file you mention is part of the
Visual C++ Redistributable package, most likely for VS 2015. I would not download it from anywhere other than Microsoft. It is safe to try that if you want. If it doesn't solve your problem, you can just uninstall it.
Like stated above though; PTF is not qualified on Windows 7, so even if it does get you running, you may hit other issues.