I am also suffering from the same issue (i.e. no log details appearing, but can save them instead) with the same version of firmware you are using. I'm using Firefox as well. I have this issue on my regular computer (i.e. linux with firefox), and didn't have an issue using another Windows XP box using IE7 connecting to the same router.
I have logged this case with tech support, but we've been doing a lot of emails back and forth, but I don't think there's any resolution on the horizon yet.
Have you been able to resolve this issue yourself? If so, what did you do?
And another thing I was wondering: are you using DHCP when connecting your computer to your router? I'm currently not using DHCP, and I thought that might be the issue, which is why I ask...
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UPDATE 2008/06/07:
It appears this is an issue moreso with Firefox than anything else. In my case, the OS (either Windows XP or Linux) doesn't make any difference; if you're using Firefox 2.0.0.6 - 2.0.0.12, the logs will not appear. Connection type (DHCP vs static IP) doesn't make any difference either. Could still be related to the most recent firmware version (2.24), although I haven't investigated this myself.