POP3 Connector errors in SBS & Exchange 2003

Hi guys, I've looked for a solution to this problem on this forum and elsewhere but am yet to find anything that works.

We run one Server with SBS 2003 SP2 and Exchange 2003. I wanted to mirror the C:\ in case of disk failure but after converting the C:\ to a dynamic disk, the server wouldn't boot. I'd already taken a manual image of the C:\ prior to conversion so I restored the image and rebooted. After all the files had re-sync'd there were a number of errors which I have been able to resolve, bar the following:

We use the POP3 connection manager to download email from a global POP3 mailbox which Exchange then distibutes to the relevant Exchange mailbox. Since restoring the C:\ image, some users (but not all) have not been receiving emails, although sending is still working. I've looked in the Message Tracking Centre and I can see lots of emails which have been sent to the users who are having difficulties, they're just not being delivered to the mailboxes.

In the Event viewer I get a number of warnings and errors after every message retreival from the Global POP3 mailbox:

The message downloading process starts and I immediately get warning event 1066, error event 1022, warning event 1067, error event 1023, error event 1019, warning event 1072, error event 1066, error event 1053, warning event 1072, error event 1066, error event 1053, warning event 1072, error event 1066, error event 1053, and finally the delivery process finished 'successfully'. The source for all errors and warnings aforementioned is POP3 connector.

I'd be hugely grateful for any assistance. I should add, I'm not a qualified IT tech, I'm an accountant (in a firm of accountants) but we don't have an IT tech as we're only a very small firm, so I've managed the server and network for the past couple of years by picking things up as I go. That said, I'm not a complete novice.

Thanks in advance guys!