This is a wonderful add-on for versions of Joomla prior to 1.5 but it is not truly compatible with J1.5.x legacy mode or not. I have spent considerable time pouring through the forums at Joomlapolis and tinkering with the component and modules as best I can and have not been able to get it to work reliably with j1.5. At best, it crashed my site only about 60% of the time.
The bottom line is that version 1.1 of CB is NOT as compatible with J1.5 as it's description would have you believe.
I will wait for both the native version of CB AND a migrator tool before I consider migrating my site.