I've found my answer. After testing with scripts calling python directly from windows command line I received a windows error about a missing or corrupted MSVCR120.dll. A little more searching and found that driver is from Microsoft Visual C++ 2013 Redistributable. I only had the x86 version. I repaired the x86 version and downloaded the (x64) version from microsoft. I can now execute external python in syntax with the SCRIPT command.
The gutter arrow and Continue Syntax Run button still not working though.