Yes, there is an extra line or two in the functions.php file that is causing this problem. If you can edit the file (it's part of the theme you are using), look at the very end where you will see a
?>, which indicates the end of PHP code. Remove any extra space or blank lines after that - the
?> needs to be on the last line of the code with NO spaces or anything after it.
If you can't edit the file, contact the theme developer and let them know they have extra space in the end of that file and ask them to fix it. Heck, even if you can edit the file, let them know so others don't have the same problem.