well i dont really know. my test site seems to be working fine. but not the actual site.
my forum actually is an old forum based on smf. i migrated to xf because of its features and all. beside this, my users also experiencing strange errors. almost similar access error.
i'll talk to my hosting on how to go about the mod_security.
just one more question. originally the xf was installed in a "forum" folder. then i moved the whole installation to the root. can that be the cause? is it possible to reinstall a fresh xf in the same location?