Odds are you either have a corrupt uisettings file
(<SERVER>_<CHARACTER>_eq2_uisettings.ini, found in your root EQ2 directory) or you don't have the necessary files to display the info center window.
If the file is corrupt, back it up (or just delete it; up to you) and replace it with a new one from the one of the optional preset files via the updater or let the game create a new one (word of caution: either or both of these methods, letting the game create it for sure will, may require some tweaking of the UI arrangement/layout).
If you are missing the necessary files, I'm sure you can come up with the obvious resolution
. But after taking a peek at the available options of files in the updater and not seeing anything directly related to the infocenter listed, I don't know if Faetyl is including it anymore. You could always try downloading it separately (found
here). Another word of caution: doing this may require you to edit some key files (Drumstix explains what you need to do by default, but you may also need to edit the .xml file for your start menu if you want to use the infocenter button to open/close the IC window instead of making the hotkey/macro Drumstix suggests in his instructions.