The sysutils/vobcopy port has code to detect the DVD device, given the mount point. It has an #ifdef to do this right for FreeBSD 5.x. However, in checking the FreeBSD version, it uses the nonexistent macro __FreeBSD_Version instead of the correct __FreeBSD_version. Thus, when built, it does the wrong thing and tries to read from the wrong device.
Fix: (tabs may be broken here, but the fix is one byte anyway...)
How-To-Repeat: $ vobcopy -m -i /cdrom
[Hint] You use -i. Normally this is not necessary, vobcopy finds the input dir by itself. This option is only there if vobcopy makes trouble.
[Hint] If vobcopy makes trouble, please mail me so that I can fix this (email@example.com). Thanks
Vobcopy 0.5.14 - GPL Copyright (c) 2001 - 2004 firstname.lastname@example.org
[Hint] All lines starting with "libdvdread:" are not from vobcopy but from the libdvdread-library
path to dvd: /dev/racd0
libdvdread: Can't stat /dev/racd0
No such file or directory
[Error] Path thingy didn't work '(null)'
[Error] Try someting like -i /cdrom, /dvd or /mnt/dvd
Over to maintainer.