Earlier this week, Fix Central was updated to prompt for an IBM ID prior to downloading fixes.
When you visit the Fix Central site, you will see the following announcement:
As of January 31, 2012, each IBM client accessing Fix Central (whether through their employees or other authorized representatives) is required to have an individual IBM ID to download fixes (some exemptions may apply). The registration is quick and simple and will provide users with a customized experience to better serve their needs. Fix Central downloads are available only for IBM clients with hardware or software under warranty, maintenance contracts, or subscription and support. Software code, samples, updates and fixes being accessed on this website (collectively, the Code) are subject to the terms of the license agreements which govern the use of the associated Code.
If you use Fix Central and don't already have an IBM ID, you can see this News item or the Fix Central site for how to get one. Keep your IBM ID handy so you won't have any delay if you need a fix.