[imp] "Could not open mailbox" error while trying to see messages resulting of a quick search

[Ezequiel Alfíe]

Hello everyone.

I've installed horde4 and imp (5.0.10).
My IMAP server is dovecot 1.1.16

When I make a 'quicksearch' on imp in the dynamic view, the messages get
listed but if I click on any of them to see the message I get an error
telling "Could not open mailbox."

(however, the message is seen correctly if I have already seen it on imp
on the same session, guess it has been cached)

Viewing horde logs I get:

ERR: HORDE [imp] IMAP error: Mailbox doesn't exist: INBOX37103 [pid
22305 on line 340 of "/usr/local/share/horde4/imp/lib/Imap.php"]
ERR: HORDE [imp] IMAP error: Mailbox doesn't exist:
impsearch+dimpqsearch [pid 22305 on line 340 of
"/usr/local/share/horde4/imp/lib/Imap.php"]

Note: I've changed MBOX_PREFIX in the file ./imp/lib/Search.php to:

const MBOX_PREFIX = "impsearch+";

Also, I noted that at the moment of making the quicksearch, this warning
is printed on the logs:

WARN: HORDE [imp] PHP ERROR: array_flip() [<a
href='function.array-flip'>function.array-flip</a>]: Can only flip
STRING and INTEGER values! [pid 22305 on line 248 of
"/usr/local/share/horde4/imp/lib/Views/ListMessages.php"]

(perhaps this is related to the issue)