[Dovecot] Errors when searching large folders

I am getting errors from dovecot when trying to search, in large Maildir folders. The folder has 40454 messages and is 371MB in size. The email client is squirrelmail 1.4.3, running on FreeBSD-current. I've had this problem before, and i posted a message here. The author said he would fix this, but it seem the problem is still not resolved.

This is the error i get:

ERROR : Connection dropped by imap-server. Query: SEARCH CHARSET ISO-8859-1 ALL BODY {5} hello BODY {5} there

At this point the HD led remain on for another 30 seconds or so.

Thanks.