Folders problem

[shakal4972]

Hi all.
first of all, thx for nice webmail - RoundCube.
i write here, because i have horrible problem with this webmail on my Debian Linux machine.
Everything working fine, but when i going to Personal settings --> Folders, page stays white and after 2 minutes browser show something about "time of this site, expired" ....

In roundcube/logs/error:
[27-jan-2009 12:02:52] PHP Fatal error:  Maximum execution time of 120 seconds exceeded in /home/WWW/roundcube/program/include/rcube_imap.php on line 2748

I don't know where is the problem.
Thx for answers.