Hello Dhiraj,
In future, *please* don't use the Ofbiz bug tracking system, Jira, for this sort of problem.
Your problem is that the line
field-type-name="postnew"
shouldn't have a name of your choice, but rather a name that identifies a DBMS known to Ofbiz, in order to find the range of data types supported by that system particular database. See
https://fisheye6.atlassian.com/browse/ofbiz/trunk/framework/entity/config/entityengine.xml?hb=true#to115for a list of values understood by out-of-the-box Ofbiz.
So in your case, you want the word "postgres" at this point.
It was the method getEntityFieldType that threw the null pointer exception, so that was a clue to the problem.
Regards
Paul Foxworthy