What does this tell you?

Warning [PHP]: Cannot modify header information - headers already sent by (output started at /home/vmc/public_html/mainfile.php:78) in file index.php line 39

myweb.com gives me this error
but if I go to
myweb.com/modules/news/ it works fine

I added a Javasript redirect to the main directory and it is forwarding the visitors to the New module.
But I would really like to know what that is since not everybody has javascript turned on.

I guess I have to expalain what happend.

The OSCommerce modules images are linked from the root directory

My XOOPS insatalletion was in the root/x/ directory so they would not show up.

So I moved all files to root and changed the mainfile.php

Now I have the Warning and a blank screen if I direct the root
When I direct via JS to a module like the news module the site works fine and the OSC images show up too.

I hope this helps.

I like to thank lykoszine for his help.

He found out that if I select none in "Module for your start page" the warning goes away.

If we select any module (News, Forum, etc) we have a warning.

I think that means there is something wrong with the redireced to a module.