mod_cron and ejabberd 2.1.6

I have recently upgraded from 2.0.1 to 2.1.6, and on startup mod_cron is not working. I am using an old version of mod_cron (I do not even know the version number, it was from the days when I use it with ejabberd 1.1.3).

Why is mod_cron not working with 2.1.6? This version has been working fine wiht 1.1.3 and 2.0.1?

Do I need a newer version of mod_cron? If yes, where can I find a pre-compiled version, please? Thank you.

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The ejabberd.log is as follows:

=ERROR REPORT==== 2011-03-18 17:24:16 ===
E(<0.36.0>:gen_mod:73) : Problem starting the module mod_cron for host "xxxxxx.ca" with options:
  [{tasks,[{23,hours,mnesia,backup,
            ["C:\\Program Files\\ejabberd-2.1.6\\backup\\ejabberd.backup"]}]}]
  error: undef

=INFO REPORT==== 2011-03-18 17:24:16 ===
    application: ejabberd
    exited: {bad_return,
                {{ejabberd_app,start,[normal,[]]},
                 {'EXIT',
                     {undef,
                         [{ejabberd_ctl,register_commands,
                              ["xxxxxx.ca",
                               [{"cron-list","list scheduled tasks"},
                                {"cron-del taskid",
                                 "delete this task from the schedule"}],
                               mod_cron,ctl_process]},
                          {mod_cron,start,2},
                          {gen_mod,start_module,3},
                          {lists,foreach,2},
                          {ejabberd_app,start,2},
                          {application_master,start_it_old,4}]}}}}
    type: temporary