ok first create a blank php page and type in the following code
run the page ie previre in your local browser and you will see if Curl is installed and functional.
on your server icon in the bar at the bottom of your screen left click, select PHP select php extensions and check ifg Curl is ticked if not thats your problem.
One thing vista home edition does not have all the bells and whistles of the pro or ultimate so that may also be an issue.
I also suspect that gallery does not require Curl because as I understand it ( I'm not an expert) it's a library that allows connections to other servers such as Https so I suspect it's related to Paypal etc.
If this does not help post back with more details. I'm in the office tomorrow all day.