No icon for un compliant GroupFolder App

Installed and active, GroupFolder icon doesn’t show up anywhere.
The firstly pre-installed then reinstalled code is not compliant according to get:check-code :
"line 12: OC_Util - Static method of private class must not be called
Database schema error: Name of table dbprefixgroup_folders_applicable is too long (24), max. 27 characters (21 characters for tables with autoincrement) + dbprefix allowed
Any idea where to find to change this data base name is welcome.

I encounter a similar problem. Activated the groupfolders app in NC 12.0.3. Cannot see any icon or user interface to invoke the groupfolders function. Deactevated, removed the app, then activated again - no change. Is there any known problem with NC 12.0.3?
Any help to make groupfolders work would be welcome - thx.