Error in Service [releaseOrderPaymentPreference]: Problem releasing payment

[Jacques Le Roux]

While trying to edit DEMO10090 order items I got an NPE in 

releaseOrderPaymentPreference[917] 
releaseContext.put("releaseAmount", authTransaction.getBigDecimal("amount"));

I fixed it using
       if (UtilValidate.isNotEmpty(authTransaction)) {
           releaseContext.put("releaseAmount", 
authTransaction.getBigDecimal("amount"));
       } else {
           releaseContext.put("releaseAmount", null);
       }
But then  I got Error in Service [releaseOrderPaymentPreference]: Problem 
releasing payment
I gave up at this stage. What could be the reason ?

Thanks

Jacques