Sometime in the last 3 months or so (I don't use the functionality often) I lost the ability to run executable files from (MS or PC)-DOS (IBM or MS LanMan requesters) if the files are stored on the samba server in mixed or lower case. The share is NOT case-sensitive, and in fact, I am able to list, move, rename, copy, delete, etc any files using any mix of case. It's only when I try to run an *.exe or *.com file that I get "Bad command or file name" error. If I rename the file to all upper case, it executes just fine. FYI I don't have the same problem executing from Windows 2000 or XP, so it appears to only affect LanMan clients. Last time I ran code in DOS from a share was about 3 months ago and it worked like it always has... just fine. The share / samba config haven't changed in that long either, but I DO regularly update Samba. Host O/S is Debian Sarge aka "Testing".
This should be fixed in 3.0.20