Summajet,
we're using Architectural Desktop 3.3 (no mechanical or civil versions, just the standard ADT), with AutoCAD express tools 2000. If you're using AutoCAD 2002, then the routine should work fine. I got both the DSTATES and LFD routines to work, but the DSTATES one isn't as necessary as the LFD one, at least not in my case. The routine that works the best is the LFD routine below (I've put the instructions that I followed to load the routine, which do work):
(princ "\nType LFD to start")
(defun C:LFD ()
(vl-Load-Com)
(vl-Catch-All-Apply
'(lambda ()
(vla-Remove (vla-GetExtensionDictionary
(vla-Get-Layers
(vla-Get-ActiveDocument
(vlax-Get-Acad-Object))))
"ACAD_LAYERFILTERS")))
(princ "\nAll layer filters have been deleted.")
(princ))
Copy it into a text file and save it as "LFD.lsp". Save it to the support folder of AutoCAD. When you start up AutoCAD, go to Tools-AutoLisp-Load. Click on the startup suite and add the LFD.lsp file. This will make sure the routine loads each time you open the program. When you open a big drawing, all you need to do is type LFD. I also like to do a "Purge All" afterwards. The LFD lisp unlocks some of the layers that came in with the random layer filters, so you can get rid of even more crap from the drawing. Save it, close it, and when you reopen it, it should be smaller.
20 layer manager filters isn't too bad. I've had upwards of 100, and colleagues of mine have had 4 times as many!
Good luck, and let us know if you get it to work!
p.s. you might want to delete the lisp routines that didn't work and start over with a new one. Make sure you go into the autolisp load menu and remove them from startup suite.