I was banging my head on this issue as well. Here was my
a. I had a pre-existing .htaccess file that activated the
necessary items (like the Rewrite Engine).
b. I didn't see the .htaccess file included in the ZIP archive
from Fork, because my computer automatically unzipped all the files
but naturally hides any file whose name begins with a period.
In other words, I didn't have the right htaccess file, and I
kept getting this error. Once I figured out there was an .htaccess
file hidden in the Fork directory on my computer, I was able to
locate it and copy it up to my server.
I suggest to the Fork maintainers that they include the htaccess
information in a non-period-prefixed file (perhaps
"copy-to-htaccess.txt"), or on a web page, for those of us who have
this issue and are either too dull or too tired to figure it out in