I do not get the ability to Insert Row or Insert Column on the Insert Menu. The ALT+I -> R and ALT+I -> shortcuts do not work either. This has happened when I just upgraded to the latest version - 5.1.0.3
Calc menus were reworked for 5.0 and further in 5.1 https://wiki.documentfoundation.org/ReleaseNotes/5.1#Reorganization_of_the_menus Those commands are now in the Sheet menu not the insert menu. Keyboard accelerators as localized.