I use Linux Ubuntu, and I've been using SamBa on a virtualized Windows XP for all my wp-34s flashing needs. But I decided I should try mySamba.exe too. And I can report that it worked very easily, directly with Wine under Linux.
As others reported, it didn't enumerate the Com ports; but I just had to write "com1:" in the com port field, and it worked on first try. Of course I had Wine setup to map the USB-Serial adapter to Com1:.
No more virtualized Windows for me!
Well, almost: I couldn't find a way to transfer the flash regions with mySamba. But for the main flashing it works great.
Cristian