Have you ever attempted to run SAP ABAP or JAVA components (or any other application) on a Windows Server and got the following error?
The application has failed to start because its side-by-side configuration is incorrect. Please see the application event log for more detail.
A quick answer is that according to Note 684106 - Microsoft runtime DLLs, SAP used different releases of the Visual Studio Compiler for Windows x86 to produce the executables for different releases of SAP. Normally, this would be irrelevant as the appropriate files would be copied on to your system via the SAPINST tool, but in my case I wanted to use my new SAPCAR before I started installing anything
The note provides instructions on where and how to download the appropriate Microsoft Visual C++ Redistributable Package. I have found, depending on your release of Windows and / or Netweaver, that you may need to download the Microsoft Visual C++ 2008 SP1 Redistributable Package and / or Microsoft Visual C++ 2010 SP1 Redistributable Package. I imagine that sooner or later, as SAP migrate to later releases of the Visual Studio Compiler, you may' end up having to download a 2012 Redistributable Package.
To get these files, go to the Microsoft Download Centre and search for Microsoft Visual C++ 2008 Redistributable Package and / or Microsoft Visual C++ 2010 Redistributable Package. There will be separate downloads for IA64 (vcredist_IA64.exe), X64 (vcredist_x64.exe) and X86 (vcredist_x86.exe). Find the appropriate Microsoft Visual C++ 20NN SP1 Redistributable Package and download and execute it.
For a much longer answer on why this is necessary, including some useful links, check out Resolving Side-by-Side Configuration Issues.