About a fortnight ago my GMail account started giving me weird errors when I tried to login via POP3; the error I was receiving was something similar to "-ERR [SYS/TEMP] Proxying required. {XDH}".
After searching for a little while to find a solution to this, I found this whirlpool thread. Turns out that Google quitely upgraded a bunch of users to the new BETA, which has lousy POP3 support. The fix suggested there is to login to your account and then put "http://mail.google.com/mail/?labs=0#inbox" into your URL bar. Problem is that doesn't work on hosted accounts like mine; fortunately it's only a small change required. The changed URL should be "http://mail.google.com/a/YOURURL/?labs=0#inbox"; replacing YOURURL with whatever is needed for your account (for me it was "timp.com.au")
PS. Yes, I did notice that I missed a week; I'll have to try to be more consistent. :-(
