Sprint HTC Hero :: HTC Mail With IMAP Server

I've tried searching for this issue around the forums, but I can't find anything similar.I bought a Hero about a month ago, and I use the Gmail app to get my Google Mail with no problems at all.I set up the default Mail app to get my work e-mail using an IMAP incoming server and SMTP outgoing server, and that's where my problem exists.When I set up the account on the Mail app, everything works great and it downloads the e-mails I've received within the last few days.After 12-24 hours, it stops downloading any e-mails into my Inbox. If I hit refresh, it refreshes without any error messages, but no mail shows up.I tried deleting the mail account several times and setting it up anew; each time the same thing happens it works for the first 12-24 hours and then stops downloading.(I can still send e-mails with no problem.I've tested that.)The strangest part is that if I hit Menu from my Inbox and choose the Folders option, I get a folders list that has some of my IMAP folders in it, but then where the list should include folders that have sub-folders, it instead begins a list of literally thousands of folder names like {33}, {51}, {20}, {27}, {22}, {34}, and so on. (The numbers in the brackets appear as the folder names, and the numbers often repeat, but not in a recognizable pattern.) Overall, the list of "folders" with those numbers in brackets is thousands of items long.