The names that I add (Kit, Starter Kit, Welcome) are all invalid. Help!

Are you talking about shopkeeper names?
What do you have configured in the config for the setting 'name-regex'?
What type of shopkeeper are you trying to name? Are you using citizens shopkeepers, or regular ones?

If you cannot get to to work with the default config:

• Try whether you also have this issue without any other plugins (maybe one is interferring with the chat handling of shopkeepers)
• What server version are you using? Try using the latest version of spigot.
• Make sure that you don't use any client mods while testing this issue.

Ok fixed it! thanks