Check if the file _main.php starts with <?php and no spaces or blank lines before <?php.

Good luck

No. I only modified the sidebar. As soon as I replaced what I modified with the original _main.php file, it started working again.

Any modification yields the error message.

Please do give us an url and the code you changed, so we can take a look.

Even the slightest change causes the error. All I did was fill in the "magnasquids link on the top and I got the error:

</div>
<div id="menu">
<ul>
<?php // PUT YOUR LINKS HERE - NOT BLOGLIST ?>
<?php /* <li class="active"></li> */ ?>
<li><a href="http://www.magnasquids.com" title="">Home</a></li>
<li><a href="#" title="">About Us</a></li>
<li><a href="#" title="">Feed</a></li>
<li><a href="http://www.magnasquids.com/forums/" title="">Magnasquids Forums</a></li>
</ul>
</div>

What editor are you using? If you're using a reasonably good document editor that could be your problem. For example "Word" will trash your php pages. I like HTML Kit but there are many editors that will play nice with php files, meaning not corrupt them with 'stuff' that makes sense for a document editor but not for a file editor.

I'm using the new Sharepoint Designer I use with my other blog. I'll try another. Thanks.

OK you did it again. Are you sure you don't want a beer or something?

And I can't believe Microsoft let me down <<heavy sarcasm>>.

It's a good program. I have to learn more HTML to use properly, however.