While trying to mount a file system, the mount(1M) command received a "Device busy" (EBUSY) error code. Several possible reasons are: this /dev/dsk file system is already mounted on a different directory, the busy path name is the working directory of an active process, or the system has exceeded its maximum number of mount points (unlikely).
Run /etc/mount to see if the file system is already mounted. If not, check to see if any shells are active in the busy directory (did the user switch to the directory by using cd(1)?), or if any processes in the ps(1) listing are active in that directory. If the reason for the error message is not obvious, try using a different directory for the mount point.