Why this syntax error in control file?

[John Moore]

I've installed monit 4.8.1 on a Debian system, from the repository. I 
cannot start the daemon, though, because of a reported syntax error in 
the control file, which doesn't make any sense to me. I get the 
following error:

/etc/monit/monitrc:20: Error: syntax error 'start'

The line in question is this:

set daemon  60  with start delay 240

To my eye, that is perfectly valid syntax according to the 
documentation. So what could the problem be? I have uninstalled and 
reinstalled monit and the problem remains. The strangest thing is that 
monit has in the past run perfectly well with this exact same control 
file. I am at a loss to know what the problem now might be, and nay help 
would be much appreciated.