I cannot seem to use Spellbook of Fate. 

As you can see in the above image, I have a Spellcaster-type monster on the field. There are 2 Spellbooks in the graveyard. I should be able to use Fate's second effect to flip Spellbook Magician of Prophecy face-down.

This screenshot is taken from the very start of my turn - no other cards or effects were active, Spellbook Magician was already on the field.

I drew into Spellbook of Fate.

At that point, that error message got spammed.

[Script error:] [string "./script/c97997309.lua"]:55: attempt to index global c"38049934" (a nil value)

I cannot activate Spellbook of Fate, only set it. To repeat, there are 2 Spellbooks in the Graveyard; Grand Spellbook Tower and Spellbook Star Hall.

Next turn; the opponent Special Summoned Tarotrei, and destroyed Spellbook Magician of Prophecy.

Next turn; I drew into Black Fang Magician (another Spellcaster). I normal summoned it. Still could not activate Spellbook of Fate - so this isn't an issue about "targeting" introduced by Pendulumgraph (even though Fate does not target).

I tried Setting 1 of those Spellbooks of the Master.

At that point, the same error messages appeared all over again, just like in the screenshot.
Michael Lawrence Dee
I'm so sorry. I applied a fix to properly check the cost. I'll fix this again to complete all that.
Now this is how I play:
No need to apologise. Thanks so much. I can confirm it's working now.