I really want to play this game, but all of a sudden I am not able to cast plant cage. One of my favorite spells. I tried reloading, reinstalling, verifying game cache, switching the ability around in my hotbar, I feel like I've tried everything. I honestly don't want to play this game knowing this happens because it could all of a sudden happen to my other abilites. I saw some other people with this issue and they all don't include a solution. Please help? I very much enjoy this game and really want to continue but I don't want to continue if I don't find a way to fix this issue.

I've come across a suggestion that it can only be cast on enemies that are not too high a level for it, e.g. Plant Cage at level 2 on enemies of no more than about level 10.