PROBLEM PHP error message

[bobbiescap]

Code:

Warning: Cannot modify header information - headers already sent by (output started at /XXX/gsconfig.php:1) in /XXX/admin/inc/common.php on line 15

Greetings all,

I am stuck on how to get rid of this error message, hosted on Hostpapa's servers, didn't occur with the Turnkey LAMP server I was running locally. Please try to keep things simple, I don't have terribly good concentration.

I did search for a solution and found a "whitespace" issue, I removed the whitespaces in the files mentioned to no avail.
Thanks in advance.