Party member turned to stone, have Stone to Flesh spell, can't use it.

[Herodotus]

So, I am currently fighting the Planar Warden, and after several attempts I finally defeated him and with minimal losses. However, one of my party, that is Rasaad, was turned to stone. Dismayed, I remembered that Aerie had learned the stone to flesh spell. However...she can't use it! Now, I am still pretty new to this game and to D&D in general, so I may be asking a really dumb question or greatly misunderstanding something here, but can someone explain why and how my level 10 mage (level 9 Cleric) is unable to cast a level 6 spell? Am I misunderstanding something? Can I come back to the planar prison later to depetrify Rasaad or is this curtains for him?

[Wicket W. Warrick]

Originally posted by Herodotus:

can someone explain why and how my level 10 mage (level 9 Cleric) is unable to cast a level 6 spell? Am I misunderstanding something? ?

Because in (A)D&D the max level that you can cast is lower that the one of the caster. Find some wiki or read the manual (or simply look at the character sheet). But you need level 12 in order to cast a level 6 spell.
And, no, you can't come back to planar prison.

[red255]

if you've done the fighter stronghold quest you should have picked up the ring of earth control which has all the stone to flesh I've ever needed.

in BG1 most of the temples have scrolls of stone to flesh, don't remember if BG2 temples do, since there aren't nearly as many basilisks in BG2. instead they have scrolls of protection from undead.

but yeah. when I start BG2 I tend to hire a thief have them drink some thief potions and rob all the vendors of ranged ammo and scrolls. so I normally have some scroll cases full of 'useful scrolls" the ammo I sell to the thieves guild vendor for gold.

in this situation I'd recommend loading a save prior to the fight if you don't have any scrolls of flesh to stone. maybe have aerie cast protection from petrification.

aside from beholder's i'm not very frequently stoned in bg2

[Herodotus]

Originally posted by red255:

if you've done the fighter stronghold quest you should have picked up the ring of earth control which has all the stone to flesh I've ever needed.

I actually wasn't aware that the ring (which I believe I do have in my inventory somewhere) had that spell. Thanks!

[Zotliatlicor]

Mages get new spell level unlocks in lvl 1 - 3 - 5 - 7 & 9 for spell levels 1-5. Then you jump to lvl 12 to unlock spell lvl 6, 14 to unlock lvl 7, 16 to unlock lvl 8 and finally you need to be a lvl 18 Mage to cast lvl 9 spells.

You can learn spells along the way that are too high lvl for you to cast, this is one of the great ways to earn bonus XP and also plan out your characters, collecting the Spells you know you will need. But you cannot memorize them into memory until you are at the correct level.

You can cast high level spells if you use the scroll, the scroll is then consumed, this is generally a bad tactic, but for some spells it is nice to have some around as stacks. Stone to Flesh / Flesh to stone is usable this way, but you may also find and/or buy 'green' Flesh to Stone scrolls from any Temples. The can be used by anyone with an Int score of 9 or higher, just as the green Protection scrolls. The Green Temple Scrolls cannot be transferd into Spell books, ie not be copied or 'learned'.

Later you may get a bunch of Freedom Scrolls (Mage lvl 9 spell). Also a nice scroll to have as a stack so it is ready when you need it. There are other examples, but it has mostly to do with playstyle and/or class style (Thieves casting Mislead and such).