This error occurs after logging to SquirrelMail.
For example I have defined filter for 'Qwerty' in
Subject and action: Move to INBOX.messages_Q
after logging in when message arrived with 'Qwerty' in
sbuject fatal error occurs:
Fatal error: Call to undefined function
if there are e.g. 7 mails with 'Qwerty' in subject
You have to refresh web browser 7 times to get into
Mail with 'Qwerty' isn't moved to INBOX.messages_Q
but is displayed in main INBOX - they are marked as D
when you replay to the e-mail, it is marked as F.
When there are 7 mails with 'Qwerty' all You have to do
is move manually one mail to INBOX.messages_Q and then
SquirrelMail will automatically move all remaining 6.
PHP Version 5.1.1-gentoo