RFC Error: Error when converting a numeric field to XML

Hi,

I am trying to solve this runtime error when executing my service from firefox rest client.

I have an entity called Expense Period (ExpPeriod) which has 3 integer fields, zmonth (abap type int2 mapped to Edm.Int16), zyear(abap type int2 mapped to Edm.Int16) and totalamount (CURR13 mapped to Edm.Decimal) in my properties in service builder.

Runtime artifacts are being generated and but it shows following error in response body:

<?xml version="1.0" encoding="utf-8"?>
<errorxmlns="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata">
  <code>/IWFND/CM_BEC/026</code>
  <messagexml:lang="en">RFC Error: Error when converting a numeric field to XML.</message>
  <innererror>
    <transactionid>1B5E32E30AD8F1F4BCAE00155D087807</transactionid>
    <errordetails/>
  </innererror>
</error>

Any ideas?