This problem easily happen when there is no python installation and there is standalone python application compiled with py2exe or cx_Freeze (e.g. Mercurial).  Such application have pythonXX.dll in its directory.  But its python library can not be loaded normally.  So an application, which loads pythonXX.dll to check if python is available and uses it if possible, is terminated when loading python.

Vim uses python as embedding scripting language.  Vim loads pythonXX.dll when :python command is used.  And this problem is reported occasionally.