Windows Installer Cannot Execute Custom Step

Question

We have a legacy WISE installer that we cannot get to run to completion. We keep experiencing an issue where the installer hangs when trying to execute a specific Custom Action that we use to configure the Databases. The custom action is a VB6 EXE.

We have gone back to older versions of our WSE file and rebuilt the install to a point that our clean install will function. Along the way we discovered that any time a new IIS application is added to the installer (in the Web Files section in WISE 7.0) the installer will hang when it gets to the custom actions at the. It seems to only hang on VB6 EXEs. We got a full install to work by creating a custom action to create the IIS application manually, but we need to have these Virtual Directories in the build so that the update can run, otherwise it will throw an error on systems with older versions installed where the installer had the virtual directories listed in it.

Even if we leave out all custom actions and try to just do a file update with the WISE installer, we cannot afterwards manually execute the VB6 EXE we need. A Windows Installer dialog will come up every time we try to run it saying "Preparing Installation" and the process we want to run will just sit there with 0 CPU use. This happens whether we run as Administrator or not. Does anyone know what might be going on?