Having trouble within Facebook setting up App error not valid URL look at this...
 

Ok within FB I was getting the error I pointed out above...
I had everything in at the top of the page where you give it an app name...
then you list it again all lowercase then
you are supposed to add your URL...
then I would get error do not include something or other....
Read this it did work just follow along and read as you go through it...WORKS

I copied this from a site...

""
i had the same problem. the error log is sketchy. this is the solution:

1st goto WEBSITE (below SELECT HOW YOUR APP CONNECTS...) and click 2nd in the text area, fill in your website http://www.yourdomain.info 3rd go back to APP DOMAIN (BASIC INFO) and type yourdomain.info This absolutely works but I didn't quite understand the instructions, so I'm going to restate them for other neophytes like myself.

1. From the Facebook development page "Apps-YourAppName", click on Basic in the LEFT Nav.
2. There are 3 sections on this page: Basic Info, Cloud Services, and "Select how your app integrates with Facebook"
3. In the Select how your app integrates with Facebook section, select "Website"
4. Enter your fully qualified domain name in the Site URL dialog box. Example: http://www.mydomain.com OR http://mydomain.com (my site does not include the www so I didn't add it).
5. At the bottom of the page click the "Save Changes" button. You may receive a notice that it may take several minutes to blah blah blah....but you can continue with the next steps immediately.
6. Now, in the Basic Information section at the top of this screen, you can now add your App Domain. This should be formatted as mydomain.com. Do not add "http://" and do not add "/" at the end of the domain name.
7. NOTE: My site does not use the www, so I cannot confirm that it's required in Step #6. Try it both ways if you're unsure.
8. At the bottom of the page click the "Save Changes" button. You may receive a notice that it may take several minutes to blah blah blah....but you can continue with the next steps immediately.
9. At this point the error was NOT displayed as it was before.

Hope this helps!
""

Ok I hope this may help someone in here like it did me.