[Jann Linder] Samba limits filenames to 26 characters. Since Mac OS X now correctly displays Windows and Samba servers in the Networks file window, users may inadvertently utilize the SMB method of logging on to Mac OS X servers from Mac OS X clients; this prevents them from seeing any files with names longer than 26 chars and anything they attempt to save this way will be corrupted in the filename to a shorter version - if it allows them to save at all.
The only way to tell if you are using the Mac OS X file-sharing vs the Mac OS X Samba windows file sharing is the fact that you will have a login box which asks for 'SMB/CIFS filesystem authentication', and it will ask for 3 pieces of information: A Workgroup/Domain, a Username and a Password. If this is the case, then filenames are limited to 26 chars and you cannot see longer filenames.
I'll have to test this! Since NTFS supports much longer file names I never thought OS X SMB sharing would truncate filenames. I find this hard to believe.