http://bugs.winehq.org/show_bug.cgi?id=21934
--- Comment #9 from Hans Leidekker hans@meelstraat.net 2010-03-06 04:58:37 --- Created an attachment (id=26638) --> (http://bugs.winehq.org/attachment.cgi?id=26638) msi: Accept null last parameter in MsiDecomposeDescriptor.
Try this patch.