Director info:'substring_1'

[dnat]

I have got the following in my director log. Couldnt infer what it means . Can anyone explain what it means and what would be the impact.

APT_CombinedOperatorController(2),0: Numeric string expected for returned value from function call 'substring_1'. Use default value.
Numeric string expected for returned value from function call 'substring_1'. Use default value.
Numeric string expected for returned value from function call 'substring_1'. Use default value.
Numeric string expected for returned value from function call 'u_string_of_space'. Use default value.

[ray.wurlod]

No, because operator combination is preventing us from determining the operator that is actually generating the message.

I suspect that you have a substring function, in a Modify or a Transformer stage, in which one of the numeric arguments is being supplied with a non-numeric value. But it is not possible to verify that suspicion from the information you have provided.