OWA password change returns IIS error: 5

Running
Standard 2003 server sp1
Exchange 2003 sp2
When trying to change a user password in OWA we get IIS error: 5. Many of our users only have OWA access due to client firewalls preventing VPN.
I have tried deleting the IISADMPWD and recreating it once and re-registering the c:\windows\system32\inetsrv\iisadmpwd\iispwchg.dll. This fixed it for a while and users were able to change passwords via OWA. Now they are getting the same errors and this procedure has failed to fix it.
It’s making me nuts. (more nuts) HELP!