If the md5 checksum(s) is/are correct then try:

When you are at the FC boot: prompt, press F2 - F4 to see addional commands for starting setup.
For example, I had to use:
linux resolution=1024x768 nofb, to get the graphical installer working right.

Try running it with:
linux pci=nosort

<edit>
I have successfully installed FC4 from DVD.
Only problem was with framebuffer for some reason.
</edit>