First of all, let me say, this IS a configuration problem, and copious reading of the documentation will sort this out for anyone willing to take the time. BUT, some people, as I would have, would rather compile, install, and go.

The problem I came across is that when I upgraded to PHP4, I copied php.ini-optimized to /usr/local/lib/php.ini (Hell, who doesn't want something "optimized").  Then I started running into all sorts of problems with my existing scripts.  Logins we failing, counters were not incrementing correctly, and various other stuff.  

I finaly noticed that all of my scripts that were having problems used global variables like "$PHP_AUTH_USER" and "$PHP_SELF", and then I did some debugging to find that these variables were empty.

FInally, I figured out that the supplied php.ini-optimized diabled global-variables, even though I had enabled them at compile-time. Basically, I think this is bad.  Since everyone, of course, is going to want their installation to be "optimized" a lot of people are going to install this version of php.ini, instead of the supplied php.ini-dist. (Yes, I realize the INSTALL file says to copy php.ini-dist, but no mention is made that php.ini-optimized might break things.)

RTFM notwithstanding, I think it would benefit all involved if php.ini-optimized were renamed to something not so enticing and so noted in the docs.

That's my lame bug-report.