Error on non-existent pages.

[webcrawls]

Describe the bug
When setting up a fresh unmodified install of SvelteKit using the given install directions on the documentation page, all non-index pages (pages that don't exist, rather?) result in an error. I am unsure if this is an issue with SvelteKit or Svelte, as I'm not very familiar with this project.

To clarify, I am on SvelteKit v1.0.0-next.74 as reported from npm run dev.
Logs
Nothing (no errors) is printed to the console when visiting a page that does not exist.
The following error is displayed on the page when visiting a page that does not exist:

TypeError: Cannot read property 'message' of undefined
    at eval (C:\Users\kscott-laptop-window\projects\test\.svelte\dev\components\error.svelte:15:41)
    at Object.$$render (C:\Users\kscott-laptop-window\projects\test\node_modules\svelte\internal\index.js:1369:22)
    at Object.default (/C:\Users\kscott-laptop-window\projects\test\.svelte\dev/generated/root.svelte:57:127)
    at eval (C:\Users\kscott-laptop-window\projects\test\src\routes\$layout.svelte:11:41)
    at Object.$$render (C:\Users\kscott-laptop-window\projects\test\node_modules\svelte\internal\index.js:1369:22)
    at eval (/C:\Users\kscott-laptop-window\projects\test\.svelte\dev/generated/root.svelte:55:122)
    at $$render (C:\Users\kscott-laptop-window\projects\test\node_modules\svelte\internal\index.js:1369:22)
    at Object.render (C:\Users\kscott-laptop-window\projects\test\node_modules\svelte\internal\index.js:1377:26)
    at render_response (file:///C:/Users/kscott-laptop-window/projects/test/node_modules/@sveltejs/kit/dist/ssr.js:377:28)
    at async respond_with_error (file:///C:/Users/kscott-laptop-window/projects/test/node_modules/@sveltejs/kit/dist/ssr.js:2572:10)

To Reproduce

• Follow the instructions on the Getting Started documentation page
  • mkdir my-app
  • cd my-app
  • npm init svelte@next
  • npm install
  • npm run dev
• After the dev server starts, visit a non-existent page (i.e. localhost:3000/hello)

Expected behavior
No error should be displayed.

Severity
This bug, while not preventing me from developing the pages I want to develop, confuses me whether I need to create a 404 route, or there is something more going on. A more graceful error should be provided at least, imo.

[webcrawls]

As #996 appears to cover this issue and provides a fix for the bug, I will close this.