http://bugs.winehq.org/show_bug.cgi?id=27425
--- Comment #4 from Hans Leidekker hans@meelstraat.net 2011-06-13 07:57:54 CDT --- (In reply to comment #3)
If the app needs to be found in the path you can run the app name through SearchPath before passing it to CreateProcess. It does seem a bit dangerous though.
It does appear to need SearchPath. Specifying 'msiexec' is sufficient to start msiexec.exe and it will start an executable from a random directory added to the search path.