Well, to answer the first part of your question, When you are downloading mail from a Pop3 server and an error occurs, it cannot directly log an error event onto your server so it creates an event such as your seeing. The key to deciphering the error is in description. You’ll note it lists error 1232. This is the actual Pop3 error that is occuring.
I did a search for error 1232 and it did not return anything very specific, but from the description of the error it appears the problem exists with a specific mailbox ‘dct-2′ which resides on the Pop3 server. I’d start by checking the mailbox configuration on the Pop server first. Make sure you can send mail to that mailbox and if successful sending mail to that point, then backtrack the path to your server verifying configuration options as you go.
Check this article out as it might help you understand what your seeing and will provide instructions as to how to set up some diagnostic logging which may shed more light on your specific errors.