Unable to change user information - MOSS RTM

Hi!

Configuration: MOSS 2007 RTM, clean installation.
We would like to enable portal users to change their e-mail addresses for
alerts. User should be able to change this information on a "User information
page" (Portal > People and Groups > User Information > Edit Item). But after
I press "Edit Item" no fields can be edited - only information about Account
name is shown on a page that opens.

I have an older MOSS installation (B2TR) where this problem doesn't occur -
users are able to edit their Account information using "Edit Item".

Can users change their user information like e-mail for alerts?

Rgs,
Zoran