I build an installer using WiX 3.5. The installer utilizes VB6 merge modules. I always get a lot of error messages from light similar to this:
error LGHT0204
The ICEs run against the final .msi package; once merge modules are linked in, the ICE code has no way of knowing which rows in which tables came from which merge modules. You can file a feature request for WiX to support running validation before merge modules are linked in, but that wouldn't let you validate other merge modules. No good solution, I'm afraid.
I too had same problem but then found pretty simple solution. Just suppress the ICE validations from the WIX project as shown below
Go to tools settings property and check "Suppress ICE Validations" box