New Post: Strange error with Win2012 R2

I've created a classic update based on a custom update (I've learned to reverse engineer it to avoid the GUI and long GUIDs). Also, no, the "can require user input" is not enabled. I've tried the package manually and it does work on Win7/2008R2, which leads me to think it's some new ACL with 2012. No real clue though. I've added the cert for the server and clients, enabled the registry key, as I have done for all other servers.

Here's what the vgx.xml I've created looks like:

<CustomUpdate>
<Action>
<ElementType>CustomUpdateElements.ExecutableElement</ElementType>
<PathToExecutable>regsvr32.exe</PathToExecutable>
<Parameters>/u /s "C:\Program Files (x86)\Common Files\Microsoft Shared\VGX\vgx.dll"</Parameters>
<KillProcess>True</KillProcess>
<TimeBeforeKilling>5</TimeBeforeKilling>
<Variable/>
</Action>
<Action>
<ElementType>CustomUpdateElements.ExecutableElement</ElementType>
<PathToExecutable>regsvr32.exe</PathToExecutable>
<Parameters>/u /s "C:\Program Files\Common Files\Microsoft Shared\VGX\vgx.dll"</Parameters>
<KillProcess>True</KillProcess>
<TimeBeforeKilling>5</TimeBeforeKilling>
<Variable/>
</Action>
</CustomUpdate>

I've bundled the 2012 version of regsvr32.exe to make sure that it should work. Same error whether I bundle the Win7/2008 or the 2012 version.