milkfloat,
I am having a terribly slow-minded day so I'm not getting it, HOWEVER:
To see if its the include that's causing the issue, try leaving the data from each PHP include page in the html file static (remove the includes and put the data in manually).
See if that rectifies the issue, as I don't see how a PHP include will cause any errors.
as:
Hello,
<php
include "name.php";
// in name.php: big.nerd
?>
<!-- is the same as -->
Hello, big.nerd
Both items are exactly the same with the exception of the first being more trying on the server (not by any measurable margin, however).
Let me know how it goes, and if all else fails, post some code if possible.
Please be sure to use [php] and [/php] tags to encase your code so its readable.
Also, if you have any database information in there such as usernames & passwords protect yourself by changing them to something obscure/generic.