OK...well it's a case of Tia Maria to the rescue!
You are in luck as I just spotted a few things Julian missed in his last clean up of the theme.
The problem is that there are issues in Moodle 2.3 & 2.4 for ALL themes that have Custom Block Regions. This means all the areas in Rocket theme, like the toplinks and the homeblock and the search, will work now that I have fixed the files. I have attatched a ZIP file here, for you so you can replace the files that have the errors.
All you need to do is change the old files...
theme/rocket/layout/general to general_old.php
theme/rocket/layout/frontpage.php to frontpage_old.php
theme/rocket/config.php to config_old.php
and then add the new general.php, frontpage.php and config.php to the relevent directories after you extract them from the zip file.
That done you will then need to disable the dock in Admin settings. As this is what is casuing conflicts within the theme.
Hopefully this will allowing you to continue customising your theme now.
PS: Nearly forgot the zip file and also tell you to enable Theme Designer Mode other wais you wont see the changes to the theme.
Cheers
Mary (Tia Maria)