sorry I use a small monitor & can’t even read the name of your variable but from what I can see:
-you have 2 blue lines pulled ‘out’ of the cast node, if the top one is where you set or used promote to variable which is created for you, then the bottom one isn’t even created yet when you try to use it.
move it (you can move it right after the one on top that sets your variable if you want to change it’s value but you’ll have to get it then add the 1 then set it again- top one doesn’t exist till after it’s set)
(you are actually creating an object or to be more exact an object reference - it’s not there when you try to add the 1 to it, not until after you create it)
-you can’t use something that doesn’t exist yet
so basically, you have to get rid of the bottom blue line you pulled out of the cast node. you can do whatever you want to with it after the set node but not before
hope that is clear
note: you can always use a print string node to see of check what your values are
also just saw that this is a Level BP, casting can be completely different in level BPs