Rapid Spanning Tree Protocol (RSTP) is needed if you want to set up redundant cabling via loops.
By default it is disabled and even if you update your DICENTIS Conference Software it will be again disabled and has to be activated afterwards. Also third party switches must comply with IEEE802:1D-20- 04 and support RSTP.
Please also note that loops have a limited hops which are lower than 21 (devices). If you need more information regarding this please have a look in the installation manual.