Unable to connect Return Value pins and Item to Find : Actor Class Reference is incompatible with BP Weapon Base Class Reference (by reference).
What is the purpose of the All Weapons array?
If anything that derives from Weapon Base will do, remove it and just use the cast to determine if the thing is a weapon.
If you are trying to further refine what is acceptable (to a subset of all derived classes) move the cast over so it happens first.