WMI CreateProcess - spawned exes are stalling

I'm using WMI's CreateProcess() to run an installation bootstrapper process (setup.exe) on a remote machine. The setup.exe is happily able to run .msi packages but for some reason it is not able to run the vcredist.exe packages that are used to redistribute the MS VS 2008 SP1 C++ Runtimes.

What I'm seeing is that the redist package is able to extract itself into a temp folder in the root of the C:\ drive, e.g. C:\a26f91763649ecad76a09d or some such, but after that the process hangs around.

I don't know what to do to debug further - I suspect that there is a modal dialog in the hidden windows station awaiting dismissal, but I can't see what the text is. Process Explorer isn't yielding much either.

Anyone got any suggestion? The problem applies equally in Windows 2000 as in Wi开发者_开发百科ndows 2008. We used to use a DCOM-based method to launch setup.exe remotely and this did not exhibit the problem.

Can anyone shed any light on what might be going on, or how to diagnose further.

Many thanks,

Stephen

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User error! My suspicion about the modal dialog was correct. It seems that invoking the setup.exe files with a relative path somehow caused the command line arguments to get stripped when passed to the nested exe, so they ran in full UI mode! Invoking with a fully-qualified path resolved the problem.