Document Manager is not working as expected

I am facing System.NullReferenceException: Object reference not set to an instance of an object for some files while extracting custom properties from Solidworks using Document Manager.

I have checked those files which has custom properties. Please guide me to fix this issue.

Hi,

I am facing this NullReferenceException when I use csv file to give input to Document Manager.

I have attached my code here.

SolidworksApi macros