Error When Attempting to Delete

I'm totally getting owned by Nintex today...LOL.

In a photo library (if that makes any difference) I set a variable to the ID number of an item I want to delete, then use the "Delete Item" action to attempt a delete, and it throws an error. Here's the relevant segment of my workflow:

"Set Variable" gets the ID number of the item I want to delete; it's noted in the history (below). The "Run if" runs if the ID > 0. Here's the Delete Item configuration:

Without fail I'm getting the following error (The workflow could not update the item, possibly because one or more columns for the item require a different type of information):

Any thoughts on why I'm getting this error?

Thanks.