I can't get the Snapshot plugin to work

Hello,

When I try to save the settings or save a dropbox destination (name) I get the following error:

Warning: Cannot modify header information – headers already sent by (output started at /home4/zara2612/public_html/wp-content/themes/columns/functions.php:1029) in /home4/zara2612/public_html/wp-includes/pluggable.php on line 896

Please help,

Ivana