[imp] mail disappearing on send

[Liam Hoekenga]

We've had a few users complain that their mail is disappearing when the hit the
send button from the message composition screen (ie, it looks like it's sent the
message, but it doesn't get stored in sent mail, in doesn't get delivered, and
I'm assuming that sendmail never gets invoked).

Out of 20k+ users, we've had a handful contact our helpdesk about this.  Any
ideas as to what may be going on here?  Horde 2.0 / IMP 3.0 / Turba 1.0, Apache
1.3.23, PHP 4.1.2, Solaris 2.6

thx
Liam