I'm looking at my rules and thinking that it looks very straightforward. So I thought to suggest you might go get the latest copy of the rules. That's when I saw that you HAD the latest version... which IS a bit messed up compared to mine.
That third paragraph in Events is what's derailing you. What it's trying to say there is that once you've rolled the dice for the Infect Regions phase, you need to completely follow through the entire phase before you can buy an event card.
My rules directly say any player can buy an event card at any time except for when the Infection Phase is processing.
Event cards are paid for and used immediately.
Does that cover it?
Thanks for the help. i went on ZMan's website for an updated rule book and they had the same one that i have with the language above in it. i was able to google it and found the rule book that you must have. we played again last night using your help above and the timing seemed right, the game clicked well even though we got stomped. ZMan needs to update their website in case there are other lost souls like me trying to understand event cards.