sharpGL in C# wpf cannot generate buffers

sharpGL in C# wpf cannot generate buffers

This simple code gives system exception and I cannot trace it since I
cannot make output to console in wpf.
OpenGL gl = new OpenGL();
// OpenGL gl = openGLControl.OpenGL; doesnt change result
uint[] buf = new uint[1];
buf.Initialize();
gl.GenBuffers(1, buf); //commenting this line out, makes the exception vanish
What could cause GenBuffers method to raise the system exception in
SharpGL.dll?
Using last version of sharpGL and .Net 4.0 targeted VS2012.