this fiddle http://zkfiddle.org/sample/skqfup/4-Array-binding-bug#source-1 demonstrates a simple case to reproduce this

The values are loaded correctly, but saving them fails, throwing this exception (trying to convert the array index into a property name)

Caused by: java.lang.ClassCastException: java.lang.Long cannot be cast to java.lang.String
at org.zkoss.bind.xel.zel.BindELResolver.tieValue(BindELResolver.java:168)
at org.zkoss.bind.xel.zel.BindELResolver.setValue(BindELResolver.java:105)
at org.zkoss.zel.impl.parser.AstValue.setValue(AstValue.java:249)
at org.zkoss.zel.impl.ValueExpressionImpl.setValue(ValueExpressionImpl.java:247)
at org.zkoss.xel.zel.ELXelExpression.setValue(ELXelExpression.java:50)
at org.zkoss.bind.impl.BindEvaluatorXImpl.setValue(BindEvaluatorXImpl.java:58)
... 34 more