Issue When Setting Localhost As Storefront Url On Local Install

I have made a copy of our store to my local machine as a development and test site.

I used Xampp and have imported the database backup. I can get into the administration, but when i try to change the storefront url i get this error.

Warning: require_once(Net/IDNA2/Exception.php): failed to open stream: No such file or directory in C:\xampp5\htdocs\store\app\lib\pear\Net\IDNA2.php on line 26

Fatal error: require_once(): Failed opening required 'Net/IDNA2/Exception.php' (include_path='C:\xampp5\htdocs\store/app/lib/pear/C:\xampp5\php\PEAR') in C:\xampp5\htdocs\store\app\lib\pear\Net\IDNA2.php on line 26

I have done that now, and it did not work. I am still having the same error.

Make sure the file exists and has the correct permissions.

I can see that the file does exist. I am not sure how to check the correct permissions, or how to correct them.