Fixed.  In imap client lib, we were using 2 digit year representation 
instead of full year representation.

Of course. And I finally did it:



S (1239141873.9424): * OK Dovecot ready.

C (1239141873.9426): [SASL-IR AUTHENTICATE Command - username: chuck]

S (1239141873.9503): 1 OK Logged in.

C (1239141873.9731): 2 EXAMINE "Spam"

S (1239141873.974): * FLAGS (\Answered \Flagged \Deleted \Seen \Draft)

S (1239141873.9744): * OK [PERMANENTFLAGS ()] Read-only mailbox.

S (1239141873.9745): * 2258 EXISTS

S (1239141873.9746): * 219 RECENT

S (1239141873.9747): * OK [UNSEEN 1] First unseen.

S (1239141873.9748): * OK [UIDVALIDITY 1161726610] UIDs valid

S (1239141873.9749): * OK [UIDNEXT 360835] Predicted next UID

S (1239141873.9749): 2 OK [READ-ONLY] Select completed.

Horde_Imap_Client: Expired search results from cache (mailbox: Spam)

C (1239141873.9774): 3 UID SORT (ARRIVAL) US-ASCII SENTBEFORE 28-Mar-09

S (1239141873.9777): 3 BAD Invalid search date parameter

C (1239141873.9799): 4 EXAMINE "Trash"

S (1239141873.9808): * FLAGS (\Answered \Flagged \Deleted \Seen \Draft)

S (1239141873.9811): * OK [PERMANENTFLAGS ()] Read-only mailbox.

S (1239141873.9812): * 1486 EXISTS

S (1239141873.9813): * 195 RECENT

S (1239141873.9814): * OK [UNSEEN 1] First unseen.

S (1239141873.9815): * OK [UIDVALIDITY 1217350064] UIDs valid

S (1239141873.9816): * OK [UIDNEXT 53306] Predicted next UID

S (1239141873.9816): 4 OK [READ-ONLY] Select completed.

Horde_Imap_Client: Expired search results from cache (mailbox: Trash)

C (1239141873.9831): 5 UID SORT (ARRIVAL) US-ASCII SENTBEFORE 28-Mar-09

S (1239141873.9833): 5 BAD Invalid search date parameter

C (1239141874.0001): 6 LOGOUT

S (1239141874.0012): * BYE Logging out

S (1239141874.0014): 6 OK Logout completed.

Any way you can run IMP in debug mode and determine what IMAP command 
is being sent to the server?

My maintenance tasks for purging messages from spam and trash folders 
run without apparent errors, but don't actually purge any messages.