String format

Can you help me with the error?
I want the script to automatically move the Link Instance to a specific workset…
later on I will add on more “keywords” , am just trying it with one instance at the moment.

Warning: Element.SetParameterValueByName operation failed. 
Input string was not in a correct format.

My bad it should be looking for the workset ID instead of string…
managed to solved it. Thanks!