[PHP] Cannot add header information

Warning: Cannot add header information - headers already sent by (output started at /home/omnidevi/omnidevices-www/s-cart/form.phtml:5) in /home/omnidevi/omnidevices-www/s-cart/shop-head.phtml on line 40 I posted this error message a few days ago and got very helpful answers...Unfortunately I can

[PHP] Cannot add header information

I know without the accompanying code there's no way to help me...But without having to get real specific what does the following message tell me is wrong? Thanks Warning: Cannot add header information - headers already sent by (output started at /home/omnidevi/omnidevices-www/s-cart/form.phtml:4