Visual C++ runtimeBlok uses the microsoft visual c++ 2008 runtime, which can be downloaded from the following link: http://www.blokmodular.com/vcredist_x86.exe (install this when blok fails to load)
Eventually when BLOK releases become less frequent the runtime libraries will be included in the BLOK installer. At present it makes more sense to keep the runtime installer (vcredist_86.exe) separate because it adds quite some bloat to your .exe downloads.