Specified argument was out of the range of valid values. Parameter name: index

Hi all,

i created one EP form (AX 2012) in read only mode, while saving my form am calling one class to process

my reqirement. at that time am getting the below error .

Message: Dynamics Object Adapter Call failed.

Source: Microsoft.Dynamics.Framework.Data.AX

Exception details:

Specified argument was out of the range of valid values.
Parameter name: index

if am not calling my class means form working fyn.

anyone help me plz

thanx.