Assuming you got windows.
Maybe its because a dll is missing as stated here: http://www.panda3d.org/phpbb2/viewtopic.php?t=4242
Just search your system for the MSVCR71.dll if you don't find it (in windows\system32) you can find it here:
http://www.dll-files.com/dllindex/dll-f ... ml?msvcr71
Just copy it into windows/system32 directory.
If you have this file, it would help if you start a sample program with CMD by cd to the directory of the sample programm and invoking the command python demo-file.py. There you should see more infos about the failure.