Hi Brain,
Try this out and see if it works for you.
I added in [string tolower[HTTP::uri]] so that your compare is in a known state (the URI Portion of a URL is case sensitive, so it is a good habit to get into to take account for it).
I also added in a logging statement, so if it finds a qualifying event it will log it into the /var/log/ltm log along with the Client IP Address.
when HTTP_REQUEST {
if { [string tolower [HTTP::uri]] starts_with "/cfide" } {
log local0. "Blocking access to "/CFIDE". Traffic dropped from [IP::client_addr]"
drop
}
}
Hope this helps.