http://bugs.winehq.org/show_bug.cgi?id=58101
--- Comment #4 from Alexandre Julliard julliard@winehq.org --- You can copy the FEX dll (libwow64fex.dll) into the windows/system32 directory, and specify the dll name in the HKLM\Software\Microsoft\Wow64\x86 key.
Your Wine also needs to be built with i386 support, i.e. configure --enable-archs=aarch64,i386.