Entering 'Blizzard' data into Kernel.bin only.
Normally, that's all you need to do for the Zolom to use Blizzard instead of Beta, if you overwrote Beta's data with Blizzard's, in the kernel. Note that you mustn't change the attack ID in Proud Clod, or it won't work (Zolom's AI tries to cast kernel spell 54h, so if the spell's Attack ID inside Scene.bin is anything other than 54h, it will crash).
If it still crashes, chances are Zolom's animation, when casting Beta/Blizzard, was altered. It happens to me, too. It's weird, because when it happens, I'm confident I didn't change this enemy's casting animation beforehand. Anyways, sometimes, the animation the 3D model uses when using one of its abilities, reverts to being 'FF' - which will effectively crash the game when the enemy will try to use said spell.
Here is what you can do : in Proud Clod, click the "Animations/Formations" button, and press the Midgar Zolom tab. You'll have a list of all of Zolom's attacks and next to them, you'll find the values for its 3D model animations, when it uses said attacks. Look for the Animation value next to Beta/Blizzard. Is it 'FF' ? If it's FF, there is your problem. Put '08' back in (=the move Zolom does when it casts a magic)(IIRC, typing 08 in won't work, you have to use the scroll bar- but maybe this was with an older PrC), click OK, then save Scene.bin.
If this doesn't fix the problem, then I can't really help you. You might have changed something important, like Beta/Blizzard's ID. Double-check if its Attack ID is still 54h in Proud Clod. This is the only important thing, as all other data related to a "kernel spell" in scene.bin, be it its MP cost, animation ID, element, status, etc - are irrelevant (the game just looks at its attack ID, which leads it to look into the kernel as to how the spell should behave).
Still, if you want an enemy to use another magic / enemy skill, it is definitely easier to edit its AI, instead of rearranging the kernel spell list. Tell me if you want me to explain how to do it
