Well I think what's happening is you aren't pressing the middle button so the logout screen on your tama will appear. Try pressing the middle button and see if you get the logout code on your tama, then enter it on your computer.
I had that same problem. I'm not sure what it might be, but it could just be your computer. Your computer might be loading a little slower. Hope this helped!
I get this too, and when I get to the souvenirs, it says "undefined undefined". The logout boxes are blank. If I could, I'd take a screen shot of it, but not sure how to do that with, what, flash?
My computer does that a lot. As far as I know, the only way to fix this is to x out of TamaTown and go back and earn the souvenirs and points again. I definitely hate when that happens.