Of note:
- Doubles support will be added eventually, but currently, other things are higher priority. I can't give an exact date, but I'd estimate a month or so.
- Protect / Giga Impact is a legitimate bug.
- The replay viewer supports all versions of Pokemon Online replays, new and old.
The message "does not appear to be a valid Pokemon Online replay" can be generated if coyotte changes the log format without telling me. Could you paste the log's HTML source code into Pastebin and paste the Pastebin link here? That would be the best way to confirm.
- Firefox 3.5 is mostly supported. You might have problems, but it shouldn't be too bad. I recommend upgrading to the latest version either way.