How to handle crmerrors in add of case through c# in dynamics crm?

I am adding case's fields data through c#. but when I am adding particular contract look up field.It gives me below error for this field. otherwise for other look up field it works fine.

I also found that this is crmerror. but how to solve that I can't find. below link displays that it is crm error.

http://www.mohamedibrahim.net/blog/2013/07/01/microsoft-dynamics-crm-2011-and-online-error-codes-full-list-api-web-service-sdk/

Error:

IncidentMissingContractDetail -2147204095 The contract detail id is missing.