I've got the same problem - on my local server and on a remote one. In frontend, changing existing events is possible, but new ones not. On storing an event the error "Call to a member function rp_id() on null" is shown.
Could it have anything to do with latest joomla update on 3.8.10?
Do you know how to fix this?
Support info local server:
PHP Version : 7.0.10
MySQL Version : 5.7.14
Server Information : Windows NT 6.3 build 9600 (Windows 8.1 Professional Edition) AMD64
Fix jQuery? : Yes
Load JEvents Bootstrap CSS? : No
Max Input Vars ? : 2500
Club code set? : No
User Agent : Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:61.0) Gecko/20100101 Firefox/61.0
Joomla : 3.8.10
component_com_jevents : 3.4.47
component_com_jce : 2.6.31
module_mod_jevents_cal : 3.4.47
module_mod_jevents_custom : 3.4.47
module_mod_jevents_filter : 3.4.47
module_mod_jevents_latest : 3.4.47
module_mod_jevents_legend : 3.4.47
module_mod_jevents_switchview : 3.4.47
plugin_content_jevents : 3.4.47
plugin_finder_jevents : 3.4.47 (not enabled)
plugin_installer_jeventsinstaller : 3.4.47
plugin_search_eventsearch : 3.4.47
plugin_system_gwejson : 3.4.44
Support info remote server:
PHP Version : 7.0.30-he.0
MySQL Version : 5.6.37-82.2-log
Server Information : Linux wp376 4.4.74-1-xenu-static-he+1+ #2 SMP Mon Jun 26 12:35:59 CEST 2017 x86_64
Fix jQuery? : Yes
Load JEvents Bootstrap CSS? : No
Max Input Vars ? : 1000
Club code set? : No
User Agent : Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:61.0) Gecko/20100101 Firefox/61.0
Joomla : 3.8.10
component_com_jevents : 3.4.47
component_com_jce : 2.6.9
module_mod_jevents_cal : 3.4.47
module_mod_jevents_custom : 3.4.47
module_mod_jevents_filter : 3.4.47
module_mod_jevents_latest : 3.4.47
module_mod_jevents_legend : 3.4.47
module_mod_jevents_switchview : 3.4.47
layout_JEventsExtPlusLayout : 3.4.6
plugin_content_jevents : 3.4.47
plugin_finder_jevents : 3.4.47 (not enabled)
plugin_installer_jeventsinstaller : 3.4.47
plugin_search_eventsearch : 3.4.47
plugin_system_gwejson : 3.4.44
Please help, thank you!