Basically all tests in the game are 3 rolls with a 20-sided dice - skills/spells are all governed by 3 attributes and you need to roll *below* each attribute to be 'succesful'. If not, then your talent/spell prowess is used to try to 'bend' the checks into success... TP* & SP* are the remains of your talent prowess & spell prowess after the check... SP* is often used in spell effects and if it is 0 after a spell check, it's possible that the spell has no effect at all even though it cost 'mana'...
I'm replaying the game as a 'warrior' so this time I can take along some other companions. Gladys can stay, though, as I quite like her occasional smart-mouthing comments.