blogger issue

Hey, this is a call for a little blogger help...I switched to a mac powerbook this week due to the previously mentioned demise of my PC latop. I'm up and running, now, but I have a problem that I've just noticed, and it is puzzling the heck out of me.

when I read some blogs, like Arbuckle's or the second chance, my browser lets me read the posts, and if I click on the date at the bottom of posts, then it lets me read what other people have posted. BUT, when I click "post a comment" it opens up another window, one that says, "blog not found". which results in the rather unfortunate and frustrating situation of being able to read comments but not reply to them. any ideas on why this is happening? Do I have a preference set wrong on my machine, or what do you think? Help!