Can't access my dashboard

I’m having serious problems and any help would be very much appreciated -thanks in advance!

I’m slef-hosting through godaddy and have already installed wordpress and the redsky theme from themeforest. I never really got the site built before I had to set it aside for a couple of weeks. Now I’m trying to go back in and customize my site and I can’t access my dashboard. When I type in the wp-admin extension to my URL, I get the following message:

Warning: Cannot modify header information – headers already sent by (output started at /home/content/15/11297815/html/wp-content/themes/redsky/lib/theme-scripts.php:1) in /home/content/15/11297815/html/wp-includes/pluggable.php on line 876

Please help…this is driving me crazy and I can’t figure it out.
Thanks,
Trey