squid and ms proxy

I have to set up a squid server as a child to a msproxy server (parent)

I am read the info at squid-cache.org and i seem to be able to log onto the windows 2000 isa server

i keep on getting error from the isa win2000 server about permissionsI have already included the password in the squid conf file

and told it who the parent proxy is (isa win200 server)
any ideas anyone has anyone done this before