Eek!
The evil
chmod 777 rears it's ugly head!
Yes,
chmod 777 will make your life easier, if you are *only* interested in making your life easier, I would recommend issuing
chmod -R 777 / now
Don't come back complaining about security issues though!
chmod 777 will make the file or directory writable by *everyone*. This includes accounts that are normally used only for system services such as apache, ftpd, ntpd, sendmail, bind, etc. The biggest reason these process run as a separate user and not root, is that this way they cannot files which they should not access. Such as /bin/ls or /etc/passwd ...
This means that if some 1337 haxx0r gains access to, for example, your sendmail through some vulnerability, he/she can only access/change a very limited number of files and (hopefully) the impact is limited.
So, in short
I would recommend you never use chmod 777 unless you have a
very clear picture of why it's 777 and not something else (One of the few examples of "legal" use is /tmp/)
----
Now, to actually answer the original question.
The guide you posted is for Ubuntu, not OpenBSD
Ubuntu is
very different.
If I understand it correctly, you want to have /var/www/htdocs/images/ writable by both Apache and by Squid?
One method of doing that is creating a new group, put both the apache and squid users in that group, and making this directory group writable (Using chmod 775)
I don't know why /usr/local/bin/flip.pl needs to be chmod 777? Since this script is executed I would consider it to be extremely bad security practice to make this world-writable! Maybe the problem you had was that it wasn't executable by everyone? Try chmod 755