Its pretty hard to guess at something like that, but I suspect it really has nothing to do with XAMPP.
I'd download a clean copy of the theme (clearly the exact same version of the theme) to your local machine, and then run a soruce code comparator. I use WinMerge, but many development environments can also compare source versions. There may have been an error in the download of the file.
If they are identical --
I can't think of any php or WordPress configuration options that would lead to that, other than php error suppression. If that code 'works' but has an error that does not affect execution - this could be the issue. PHP is very forgiving. In your XAMPP/php/php.ini search for an uncommented line beginning with 'error_reporting =' (it should be around line 514)
try using this value: (it will turn off notifications)
error_reporting = E_ALL & ~E_NOTICE & ~E_DEPRECATED
Also a few lines in the php.ini, down there is the value
display_errors = On
That may be set to Off on your host's server (i.e. no error messages are output -- this means you don't know if they exist if the code does not fail.). You can find the settings your host uses by either finding their settings in Help or an FAQ or uploading a phpinfo.php file into a public folder on your hosting account and executing it in your browser.