By the way, disable mod_security via .htaccess it is known to cause issues with katz.
Code: 
#
# If mod_security is enabled, attempt to disable it.
# - Note, this will work on the majority of hosts but on
#   MediaTemple, it is known to cause random Internal Server
#   errors. For MediaTemple, please remove the block below
#
<IfModule mod_security.c>
	# Turn off mod_security filtering.
	SecFilterEngine Off

	# The below probably isn't needed, but better safe than sorry.
	SecFilterScanPOST Off
</IfModule>