Error? HELP!!

[Ravallojr]

When viewing my forum, when I try to go to the direct link I get an error. The direct error is

"Warning: Cannot modify header information - headers already sent by (output started at [path]/showthread.php:1) in [path]/includes/functions.php on line 3968 "

Is there anyway to fix this or should I contact the host?

[kh99]

Is that the only page that gets the error? Try looking at your showthread.php file, the very first line should be <?php with nothing before it.