Although I now run v8, I too used to run v4.0d silver edition. I had this problem at some point as I kept the solution. I don't know if this will help but here was the solution:
A required file, ctl3d.dll, is no longer included with the Windows XP Operating System. You will find the file on the TMG 4.0c installation CD, on an older computer or download here. If you download the ctl3d.exe file, run the file to extract ctl3d.dll and place the file in the /tmgw/ folder.
I am unsure if the link works properly. It was: http://whollygenes.com/ctl3d.dll
Alternativley, search this forum by just putting in ctl3d.dll and a few old posts come up that might help you to get this file.
Edited by Elderflower, 17 November 2015 - 02:45 AM.