One (1) Calendar Issue

URGENT!!!

Dear All,

I 'm facing a problem with clander like;

One i give duration One day e.g: activity start on 12/10/2010 and will be finish on 12/10/2010 than this will be consider one right duration  But with me on the schedule date is comning 13/10/2010 instead on 12/10/2010 and showing the org. Duration is 1 (one). Can some one fix this problem. this will be much appriciated.

Regards,

maqeel

(maqeel2008@hotmail.com)+966599981584