HELP!!! Why can't I throw my sword when my hearts are full?

What quest? Some quests (such as newfirst) have sword beams disabled for the weaker swords.

I don't know which version it is, it was the only one I was able to get to work. How do I enable it?

Is this the quest that starts right after you enter your name without loading any custom quest?

There are many quests that are like that (hidden Duillity and others,) Just remember it is an option under initial data and can be used to make the quest more challenging! You could try it and I tryed it myself. It is not really good to make no shoot swords but a game does need a challenge.