It turned out that my router was to blame. Apparently, D-Link routers don't work well with Linux - when you connect to it, it should forward you to your ISP's DNS, but instead it directs you to the router. Not quite sure I understand it, but I've resolved the issue by using Open DNS and changing a few text files.
I'm very relieved that I've got Gutsy working. Feisty was great, but there were reliability issues with it - it wouldn't display the splash screens for when it was loading up, and sometimes it would get stuck when closing down. Also, there's lots of goodies in Gutsy I wanted - Iceape, Thunderbird 2, Pidgin, etc. But most of all, I wanted a better wireless experience. There are two reasons Gutsy is better in this respect than Feisty:
- Feisty had a driver for my wireless card, but it didn't support WPA, so I had to blacklist it and use ndiswrapper to run the Windows drivers, which was tiresome.
- Gutsy has the 2.6.22 Linux kernel, which apparently is the first to feature a brand new wireless stack, making it much more reliable.
Now, that does mean I have to spend ages putting back all my applications, but I think it's well worth it for a more reliable wireless connection and more up-to-date software, don't you?