I did some research into the error message I get, but all I can find are discussions that reference Microsoft support pages that no longer exist. The links are these (I won't include the actual links, since they lead to a 404 page):

Illegal Operations or Access Violations When Starting Windows (Q175930)
Explorer Caused an Invalid Page Fault in Module... (Q191609)
Error Message: Explorer Caused an Invalid Page Fault in Module Browseui.dll (Q293174)

I'm thinking I might have to reinstall Windows 98, but I'd like to know if this is somehow related to the m3D or its drivers, or something software related, or something else entirely.

Here's the full error message:

EXPLORER caused an invalid page fault in
module SHELL32.DLL at 0167:7fcb1946.
Registers:
EAX=00004e87 CS=0167 EIP=7fcb1946 EFLGS=00010202
EBX=00000000 SS=016f ESP=005ffb40 EBP=005ffb54
ECX=00004e49 DS=016f ESI=80000000 FS=25f7
EDX=0044bb19 ES=016f EDI=00000000 GS=0000
Bytes at CS:EIP:
66 8b 0a 66 85 c9 75 f1 c2 04 00 ff 74 24 04 ff
Stack dump:
7fcc2b3e 00446c94 005ffbec 80000000 00000000 005ffbac 7fcbaa2d 00000001 00000000 00000000 0000cbf8 00008003 0c02b7ff 00000001 00446c94 fffceac3

If I disable Active Desktop, it changes from saying "module SHELL32.DLL" to saying "module BROWSEUI.DLL"