it looks like those errors are because you’re calling on the gun actor that isn’t there. You can reattach it but take note:
attach it after you are able to move the character (even without animation). This is to exclude the gun from further testing.
You say you are able to move again after detaching “certain nodes.”
That’s forward movement, but only if we can be certain of which nodes. We need to know which nodes those are. You can add them back in bit by bit to see which one breaks it.
Add a node → test → add a node → test
until it breaks!