Cleric L11 missing skills---HELP!!!

[GEEZER]

A level 11 cleric that I've had with me since day 1 is now missing the spells she should have in skill levels 4,5&6 when we go into battle. Yet, when I go to the character menue they are all still listed! That is, levels 1 through 6 are still shown, the way they are supposed to for a L11 cleric, EXCEPT all the "remaining quantities" for those spells in skill levels 4,5&6 are shown as "0"!
In battle, I can only access levels 1,2&3 as the other three are not shown at all!
Would someone please explain what the hell has happenened to a valuable member of my team, and more important, how do I correct it? And going back to a saved game is not an option. I've gone back through all 15, and this screw-up exists in every one of them and I know it just happened!! History revised!

[theCheat]

what is your cleric's wisdom? if it is not high enough, you will not be able to access the higher level spells.
your wisdom will need to be atleast 14 to cast level 4 spells I beleive, 15 for level 5, 16 for level 6 and so on
that's all I can think of, unless somehow an undead drained your wisdom, but I don't think they can affect it.

you might have also equipped an item that lowers your wisdom too, check that out

[GEEZER]

You sir, are a genious! My clerics wisdom level was down to 13+1. So I checked the recent armor replacement, a piece called Nezras's Mysterious Chainmail, and buried in the small print is WIS-3!! The cleric's wis level is back to 16+3 and so are all the spells, back that is....I will be a lot more careful in future.....than you very very much!!