calendar path is overwriting.

i have installed calendar on my site.
its working fine but the path is over-writing.
i.e.
http://www.example.org/http://www.example.org/calendar/2012-09-01

it should be only
http://www.example.org/calendar/2012-09-01

it is happening for all day, week, month, year.

help me asap.

thanks in advance.