Thanks for the followup!
The router came with FW 1.01.
Should I upgrade it to 1.03?
I'm using Win 7 and XP, and running the latest Java (v1.7.0_15).
I tried FF but the java applet plugin is disabled. So I use IE8, where java applet runs with no issue.
Like I said, when I got to mydlink.com to access my router the first time, I could connect to my router. After that, it stopped working.
From what I can tell, when I log onto mydlink.com, the java applet running on my PC just talks to the mydlink server via https. mydlink server tries to connect to my router and sends the info back to the applet. When I see "Unable to access your DIR-826L" error message, it means that the mydlink server can't access to the router, right?