I have a vendor-provided MSI with ISScript1150.msi prerequisite.

On Win7 x64 I get this in the msiexec log:

1: GetInstallDriver, Can not find InstallDriver in ROT table, Return Code = 0x80004005
1: {640C9EE4-0C22-4C64-BAE2-CFEFCE1C8CFC}
1: Extract supporting files
1: Failed to extract _IsUser.dll, Ignore it.
1: Failed to extract IGdi.dll, Ignore it.
1: ISMsiServerStartup Failure, Failed to Initialize script support, Error = 0x80010105
1: MsiServerStartup failed. Abort installation.

Works fine on Win7 x86 and WinXP.

I installed ISScript1150.msi with a .mst that changes the AppID Run as entry. I verified in DCOMCNFG that the components are set to run as Launching user. I even inserted a VBscript before ISMsiServerStartup that iterates and sets Launching user. None of this has changed the result above.

Is there some other cause, some other fix? Or am I doomed to capture and repackage this MSI?