Smoot's post in Error on launch game witch mono on Ubuntu was marked as the answer
See what version of Mono you're running. If you straight up use apt to install mono it might give a newer, but not working, version. You need to point to the repo in the below thread to get the right version.
Check this thread out.
Smoot's post in Add Tool Types and Translation EquipTypes was marked as the answer
Did you put a comma after the fishing rod line as shovel has?
Post the snippet after your added tool.