In a previous post I wrote a little function to convert HTML to PDF. I wanted to use this function on a server and start it with an event. The silly thing was that nothing happened. Later I figured out that the program crashed. It threw a FileNotFoundException with the statement "PublicToken = 8354ae6d2174ddca", but the DLL was there and the reference was correct too. Soooo I had to figure out why the error appeared.. It took a wohle day, but now I can present a solution. The architecture of a server stores assembleys in a Global Assembley Chache (GAC) to use them. So the server was looking for the assembley in the GAC and that is why the server was not able to find it. Right now the FileNotFoundException seems to be logic.