I've created a field dedicated to external urls: https://github.com/burnbright/silverstripe-externalurlfield

That linkable plugin opens up a field but displays nothing and shows an "Internal Server Error"?

Any ideas what could be wrong? Module is plugged into Root Directory and database has been built.

@Piixel Designs Check your Silverstripe environment is set to dev mode, and check your PHP error reporting is cranked up. This should allow you to see more information about the error. If you don't understand the error information it gives you after doing this, post it here and I'll see if I can help.

I have it all cranked up and it shows perfect error messages, however it just says server error and I can't seem to show any other error message?

Ahh, maybe it's an error occurring in the ajax request that gets the html for the popup. In this case, have your web inspector or firebug panel open when the request is made, and in the network tab you can see all of the information about the failed request. Should be some better error info there.

Appears to be something breaking in the jquery.js file (should there be a specific file to use?) I am using the below version:
http://code.jquery.com/jquery-latest.min.js

Cheers

Not sure, I don't know enough about the code you're running or the error that's occurring. I'd suggest posting an issue on stack overflow with as much information as possible about your issue, particularly the actual error message