Process Error: (Invalid index (0) for list: valid range is 1..15) (Data Outputs)

Hi All,

I'm getting below expression error when in one of the script task outputs:

Expression error: An error occurred while evaluating expression: emailDetails:pv!taskDetails[pv!counter] (Invalid index (0) for list: valid range is 1..15) (Data Outputs)

The output of the script task where this error is occuring has this expression:

pv!taskDetails[pv!counter] saved into target of email_details of type taskDetails(CDT).

Please suggest if anyone had an experience of the same error. Thanks in advance.