Some more detail would be appreciated; but I can make a couple of observations:
What changed between the time it was working and the time it wasn't?
"Seeking" is when you jump directly to a certain location in a file, instead of reading through it until you find what you want. I don't know why include() would be trying to do this, but even if it was, you can't seek through pages being returned by a web server (because you have to wait while the web server serves up everything before getting to the bit you're waiting for).
If the index.php being included is a file on the very same server as the file including it, is there some reason in particular you're asking for it via a URL and not as a file?
