http://bugs.winehq.org/show_bug.cgi?id=16994
--- Comment #2 from Hans Leidekker hans@meelstraat.net 2009-01-18 06:22:30 --- Created an attachment (id=18789) --> (http://bugs.winehq.org/attachment.cgi?id=18789) msvcrt: Unwrap wide open functions.
The problem is the wide versions of the open functions are implemented on top of their ansi cousins, which entails a lossy conversion.
Can you try this patch?