I have created new GL Account. When i tried to post the entries to the GL system is giving some waring message which says "Account No xxxxxxx is not defined as can account for the Vocher sub type Contra and Doucment No.xxxxxxxx"
Welcome to forum,
From the context of your msg I suppose you have missed something in setup - but, as you use Indian localisation, which is very specific, precise answer can give only forum members who know this localisation well.
Therefore, I moved your post to Indian forum, as a newcomer you might not know that such exists here. Common questions can be posted anywhere, but if you have issues with Indian localisation, please post them there, so they sooner will catch attention of people, capable to help you.
You have add the record in Voucher Account table for the same.