Activities->notes yields "Failed opening required '' "

[idccomtek]

Clicking on the Activities tab and then the "Notes" shortcut displays a search box, but, underneath the "Search, Clear, 'Saved Searches'" controls, it displays an error:

Fatal error: SugarBean::require_once() [function.require]: Failed opening required '' (include_path='/var/www/sugarcrm/include/..:.:/usr/share/php:/usr/share/pear') in /var/www/sugarcrm/data/SugarBean.php on line 3151

Everything else seems to work okay, but this problem affects all users.

Can anybody offer any suggestions, please?

Thanks,

Ian

Software details:
mysqld: Ver 5.0.32-Debian_7etch5-log for pc-linux-gnu on i486 (Debian etch distribution)
kernel: 2.6.18-6-686
php: 5.2.0-8+etch10
apache: 2.2.3
sugar: 5.0.0b community

[Leibinz]

I have the same error when accessing tasks under activities - any ideas?