I had a following problem. After reinstalling my OS (linux) my gl programs caused an access violation error. It was very strange because they worked fine before the system reinstall. It occured that GLU lib was not loaded and a call to gluPerspective caused access violation. The problem is that there is no way to check if GL, GLU and GLUT libs are loaded properly. I think it would be a good idea to change this the way it is done in glx.pas.