Undefined index

Hello, Your theme works great for me on my local copy – but then I uploaded to the server and when I get to the WordPress admin all the styles are gone and I get an error about a Undefined index: host in /my/server/path /wp-includes/theme.php on line 1944, line 2003.

Note: I’m using a subdomain, but that has not caused me any issues in the past.

Any ideas?

Thanks!