There is a problem in the database table _os_cck_categories. It does not have an index (published) it is said.
Please not take attention to this. I not know why Joomla added this, but this work not always correctly. In new version OS Joomla CCK we remove this warning.
We moved all rent features to Pro version our Joomla CCK
- Booking calendar field
- rent requests manger at backend
- "rent history" for some user
- "rent history" for some instance
- "layouts of rent"
Now only on Pro version Joomla CCK. This permited to us have free version package file size less 2 Mb. This permit simply install it to all free and share hostings without additional configuration steps