Developing Firewalls for Windows 2000/XP

Question

Hello

          I got a code from CodeProject for blocking and unblocking urls. Link is
     "http://69.10.233.10/KB/IP/drvfltip.aspx?display=PrintAll&fid=13906&df=90&mpp=25&noise=3&sort=Position&view=Quick&fr=226"

It was working on my system but last five days it is not working . Means its giving problem for loading "DrvFltIp.sys". While i am checking with Getlasterror() its giving value 3 i.e "The system cannot find the path specified.". Who is already faced this type of problem and solved it please send me the solution so that i can solve this problem.

Thanks, Kamal