my password meets the requirements and i bid highest but the snipe did not work - the snipe HAS worked - WHY did it all of a sudden just not work this time??

Sniping does not guarantee winning. You have to meet eBay's and seller's requirements in order to win.

You did not provide the item number so I can not check what happened, but you can always check for the exact reason by looking at "My Status" field.

Hi. It was item number 300471037444 - and where is that window? I am using the FF plugin

You can login to your account at http://www.myibay.com/ using your eBay user id and password to manage your snipes and see all information.

I checked your item and I see the following:
"The seller doesn't ship to the location of your primary shipping address"
It seems you did not meet seller's requirements in this case.
You have to ask the seller to either remove this restriction or add you to the exception list of allowed bidders.

In the future, when not sure, please try to put a manual minimum bid to see if it goes through. If it will, your snipe should be fine as well.