[squid-users][squid 2.4] unable to load pages with scripts

Hello all,
I have just installed a second-level Squid 2.4 cache (the first-level cache
proxy being an mod-proxy Apache 1.3.22).
It appears that the Apache proxy works fine, but I have a problem while
using the squid one when I try to access web pages containing a script (any
one, javascript, PHP, java, etc... or even a simple HTML form) : then I just
go to timeout , whatever the browser I use, so it must come from proxy.
I add that the Apache server is the only machine allowed to access the
Internet (every other machines are restricted to the local network).

Any idea?

Grégory Luguet

For interested peoples, here is my squid.conf file's attached