Is anyone else having issues with the calendar module or is it just me?

When I activate the calendar module, it blanks out the entire page.

Yep, I can't load a page either.  I get this error:

Fatal error: Call to undefined function mb_substr() in /.../public_html/modules/mod_lb_calendar/helper.php on line 110

Any ideas or fixes for this yet?

I hope the calender will be something like the Eventlist calender mod

example here: http://extensions.joomla.org/extensions/calendars-a-events/events/3993

Maybe you can borrow a lot from this mod?

rgds