I also have an issue with newly installed clamav plugin. Once I try to access it's config page I get:
Failed to execute XPath query '//services/clamav'.
OMV\Config\DatabaseException: Failed to execute XPath query '//services/clamav'. in /usr/share/php/openmediavault/config/database.inc:78#0 /usr/share/openmediavault/engined/rpc/clamav.inc(60): OMV\Config\Database->get('conf.service.cl...')#3 /usr/share/php/openmediavault/rpc/rpc.inc(86): OMV\Rpc\ServiceAbstract->callMethod('getSettings', NULL, Array)
Could you please let me know how possibly I could approach this?