http://bugs.winehq.org/show_bug.cgi?id=4709
------- Additional Comments From hans@it.vu.nl 2006-14-03 04:25 ------- Mounting a network drive isn't supported no, but note that your program would also exit on a Windows machine that is not part of a domain.
That said, Samba allows you to mount Windows network drives, it's just that Wine is not (yet) integrated with Samba so that it's possible to mount network drives by calling Windows APIs.
You may still be able to trick this app by returning success from the API that is supposed to mount the network drive. Then setup a Samba mount by hand and use winecfg to assign the expected drive letter to the mount point you created.