Hi Ashish,

i hope i have a solution for you.
as i wrote before you need to write error messeage for every field which
will be validated as i described before.

to show a better message as infopath do you can use this lines of jscript:

try{  
  if(XDocument.Errors.length!=0) // analyse are there some errors in the form
  {    //show the message of the first error in the form
    XDocument.UI.Alert(XDocument.Errors.Item(0).DetailedErrorMessage);
  }
  else
  {     //submit the form to a database
    XDocument.Submit();
  }
}
catch(ex)
{
    XDocument.UI.Alert(ex.message);
}

put this lines of source in OnClick event of a button.
if there is an error user will see your customized message for the field.
if ther is no errors in the form the form will be submitted.

cu

Andrej