QUOTE (cimbronemamma @ Jul 14 2009, 03:27 PM)

Was their a solution to this? I'm getting this same error message:
Task 'mail.christmasattic.com - Receiving' reported error (0x800CCC90) : 'Your incoming (POP3) e-mail server has reported an internal error. If you continue to receive this message, contact your server administrator or Internet service provider (ISP). The server responded: -ERR unable to open that message'
The only thing that has happened is an email address was added yesterday. This error message is not affecting everyone. Just one person that we can tell.
I ended up finding an email "stuck" in the NetSol system. I don't recall the details but I remember that it was pretty easy to recognize when I logged into the web based system. I manually deleted that email and the problem was solved.
BTW - the spport team that was supposed to help me took a week, provided no assistance and sent me an email a few days after I fixed it myself that said "the problem appears resolved so we're closing the ticket." (paraphrased). The person that did help me was someone on the chat line who said "It's not my team but the problem is usually a stuck email."
That was all I needed to track it down. I hope it's enough for you. If it's not, you at least have a starting point when you call support.
Good Luck.