Platform: PC
ISP: Bellsouth Fast Access DSL (or AT&T)
Type of Internet Connection: DSL
Internet Connection Speed: 3.0mbps
Date & Time: wednesday november 7, ~7-10pm central standard time
Frequency: approx ~5%-10%
Character Name: Raksha
Race: Hume
World: Lakshmi
Main Job: SCH
Support Job: RDM
Area and Coordinates: Abyssea Konschtat, among the Shadow lizards near the martello
Party or Solo: Solo
NPC Name: N/A
Monster Name: Shadow Lizard

1) Use Alacrity
2) Cast Thunder5

3) Use Alacrity (optional)
4) Attempt to cast thunder5 again
5) Receive "Unable to cast spells at this time" or whichever message, even though the cooldown timer has expired



Basically it looks like occasionally the game thinks your nuke/spell/whatever is still on cooldown, even though it isnt.