If you receive error 1691 (Library file "fgl.fll" is invalid) after launching sample1.exe
try to follow the guide proposed by Igor Korolyov (at http://forum.foxclub.ru):

1) Download new release from http://fgl.codeplex.com
2) Install "Visual C++ 2012 Redistributable Package" (download it through microsoft.com)
3) If you still receive error 1691, install "Visual C++ 2008 Redistributable Package" (download it through microsoft.com)
4) If you still receive error 1691, install "Visual C++ 2005 Redistributable Package" (download it through microsoft.com)

And also you should have installed Microsoft Visual FoxPro 9.0 and later.