Thanks ZK-LGD. Success!

It does work.
I used the text you posted and there were no problems. I tried again with the VATSIM weathers. There's a garbled bit in the middle of the file that ends in 'user-agent: yandex' and this causes FSMetar to reject the file. It worked fine when I took that bit out. It still doesn't like the IVAO text file though, there might be an error in it somewhere that I haven't noticed. NOAA seems good though, with better coverage of Australia and Pacific sites. How did you get the file in the format you posted though? When I go to the URL, I get the weathers in a format like this:
2007/08/12 23:45
KRUQ 122345Z AUTO 00000KT 10SM CLR 32/21 A3000 RMK AO2
2007/08/12 23:50
KVUJ 122350Z AUTO 00000KT 10SM 32/17 A2999 RMK AO2
2007/08/12 23:45
KRUQ 122345Z AUTO 00000KT 10SM CLR 32/21 A3000 RMK AO2
[Edit] I've got it all working now. It can be a bit temperamental and it limits itself to just how many METARs it will load (more than a thousand shouldn't be sniffed at). Otherwise, it looks like a good utility.
Cheers,
Dan