BB Curve :: Not Receiving Some IMAP Emails?

After initial setup, I'm able to receive SOME, but not all, e-mails on my BB Curve 8530. The others not received on my BB DO appear in Outlook 2007. I can't seem to identify any difference between those e-mails I receive on the BB and those I don't. On the recommendation of my web hosting company, I'm using their IMAP server. POP3 remains an option too. I have completed the registration and reconciliation processes. I've consulted with my web hosting company, and with both Verizon Wireless and RIM;