how to set Date

I'm using Mantis BT 1.2.15 and Project management plugin 1.4.0.
I'm unable to set the target dates for work types, when I click on the "calendar Icon" to set the date the window goes to top and the link in the browser shows as below:
http://192.168.10.211/mantis/view.php?id=3916#targets [^]
and no way to get the calendar even I've tried on multiple browsers