That sounds like DCOM Permissions issue. What account is your EXE running under in DCOMCnfg? And what account is your Application Pool set to? I suggest using LocalSystem and if you do you should not have problems accessing COM objects on your server.
Also make sure that the server is registered and can be loaded on its own from outside of IIS. Look in the docs for how to test your COM server either with a small VFP program or a VBScript test script.
Links:
+++ Rick ---
from Maui, Hawaii