"Number of items" cannot be altered.

In /workspace/configure,
"Number of items: Maximum number of items to display in your workspace" cannot be altered.
I alter the number, and press "Save configuration", then a message "Please enter a numeric value." appears.
Even if I re-imput the default number (50) and press "Save configuration", the same message shows up.

Server OS: Linux
Web Server: Apache
PHP Version: 5.2.2
PHP interface: cgi
MySQL Version: 5.1.19
My client OS: Windows XP

Thanks for this module for 5.x. I have thought it very useful!