xmlTVNZ relies on website to pull the information from - if something changes with the website or the site is down or overloaded it doesnt work.
The listings available at http://epg.pvr.geek.nz/epg/ are pulled directly from the D1 satellite feed - Freeview and SKY channels updated twice per day and including a blurb about the shows - like the sky decoder epg has.
Further info on this (and a download tool- http://18.104.22.168/epg.exe ) can be found at - www.geekzone.co.nz/forums.asp?ForumId=34&TopicId=16290
Going by Revens details ther are over 300 people who have paid for xmlTVNZ - assuming an average $20 "donation for development" Thats $6000!!!! and $20 is probably a "nice" estimate - Its not a donation if you have to pay to get something, ITS A PURCHASE.
Just trying to save you guys getting ripped off for an unreliable way of getting your guide info, if your happy stick with it, but there are alternatives for those who are unaware.