What steps will reproduce the problem?
1. Upon deleting post or thread

What is the expected output? What do you see instead?
Post is deleted, but this error is displayed:

"Post successfully deleted.

Warning: Cannot modify header information - headers already sent by (output
started at /home/user/public_html/board.php:442) in
/home/user/public_html/inc/func/misc.php on line 75"

What version of the product are you using? On what operating system?
kusaba 1.0.4; FreeBSD 7.0

Please provide any additional information below.
Any ideas would be greatly appreciated - thanks!