That command seems to work OK here in Opus 12, as long as it is set to MS-DOS Batch (since it uses the DOS "type" command).
You can create empty files without using external commands, however. This works when set to the normal mode, and will also work in more places (e.g. if UAC elevation is required to create the files):
@nofilenamequoting
FileType NEW=.txt NEWNAME="norename:{file|ext=seen}"
Delete