I figured out why the EXE was hanging, due to a combination of factors including not setting UDFPARMS to REFERENCE and trying to use MESSAGEBOX. Now the EXE works, but I want to get the DLL to work. I can get it to run in the development environment, but not when the main application is compiled as an EXE. It causes an invalid instruction in VFP500.DLL as CREATEOBJECT is executed for the class in question. The class is just an empty stub (no code in init) and the main program for the OLE server class has no code save a RETURN. The inproc server is much more acceptable for my purposes. I unregistered the outproc server, and RegSvr32 registers the DLL sucessfully.
All the machines have the VFP DLLs installed. The code to instantiate the object is simply:

oReports = CREATEOBJECT(c7Reports.ReportCode)

The error I get in NT usually reads something like this:

The instruction at "0x100bbb5e" referenced memory at "0x00000064". The memory could not be "read".

In Windows 95 I get:

C7BRIEF caused an invalid page fault in
module VFP500.DLL at 014f:10007b5d.
Registers:
EAX=00000000 CS=014f EIP=10007b5d EFLGS=00010216
EBX=00a7f068 SS=0157 ESP=0063de10 EBP=0063e124
ECX=3ffe6499 DS=0157 ESI=00a7f068 FS=13a7
EDX=fffffffc ES=0157 EDI=009e8000 GS=0000
Bytes at CS:EIP:
f3 ab 8b ca 83 e1 03 f3 aa 5f 5e c3 56 57 8b 01 
Stack dump:
0000000e 0063de1c 10007946 4e454700 4c415245 01b50000 00000574 494e5500 00545751 01b50000 0000078b 54554400 00004843 01b50000 000009ae 45434900

Hmmm.