TypeError: Arguments to path.join must be strings

[anhk]

gitbook serve --port 80

Live reload server started on port: 35729
Press CTRL+C to quit ...

info: 12 plugins are installed
info: 7 explicitly listed
info: loading plugin "prism"... OK
info: loading plugin "toggle-chapters"... OK
info: loading plugin "search-pro"... OK
info: loading plugin "livereload"... OK
info: loading plugin "fontsettings"... OK
info: loading plugin "theme-comscore"... OK
info: loading plugin "theme-default"... OK
info: found 83 pages
info: found 14 asset files
warn: "options" property is deprecated, use config.get(key) instead
init!
warn: "page.progress" property is deprecated

TypeError: Arguments to path.join must be strings

[zilan920]

I am having the same problem, it seems like you have fixed it ,can you tell me how? thanks