The original Imbalance2 theme includes functions that remove some of the default WordPress Gallery features. You can find these functions in your theme's functions.php file.
Since the Carousel module hooks into the core WordPress gallery feature, it cannot hook into a modified version of this gallery.
To work around this issue, you'll need to remove these custom gallery features from your theme.
Another solution would be to download and install another version of the Imbalance2 theme, available here (the download link is at the bottom of the sidebar on the right):
http://theme.wordpress.com/themes/imbalance2/
I hope this helps.