The command line you specified is incomplete. Usually, a command line argument has been omitted or a switch was placed after the other arguments rather than before.
The same error is issued when you attempt to invoke ezmlm-make(1) with only the ‘DIR’ argument without using the -e or -+ switch. Other command line arguments can be omitted only when editing lists created or previously edited with ezmlm-make from ezmlm-idx>=0.23.
Some special situations use ezmlm-make(1) as a general script processor, e.g. the setting up of sublists with ezmlmsubrc(5) and of a global interface with ezmlmglrc(5). Here, there is no ‘memory’ so all arguments have to be specified, even when using the -e or -+ switches.