InstallUtilLib.dll: Unknown Error again

[Konstantin]

I'm investigating InstallAware using. Trying to re-implement MSI installations I have now I've found that when I add MSM module with custom actions InstallAware installation fails with error message:

InstallUtilLib.dll: Unknown Error

The error text is varies when MSM is created under VS2005 and VS2003. Different messages appear on different operational systems. But all of them failed. The custom action dll is successfully copied into "TARGETDIR\\Module Retargetable Folder\\" folder. But it's not executed.

The MSM module I used successsfully works inside of MSI installations. It cannot be replcaed by InstallAware plugin because I'm planning to use it from both MSI and InstallAware installations.

I've also tried creation of very simple merge module in Visual Studio with simplest custom action. An InstallAware installation that contains just this merge module fails.

What should be done on Visual Studio and/or InstallAware sides to avoid this failure?

Thanks in advance -

Konstatin