Upgrading PHP

Hi,
I have this annoying problem and I was hoping it was a familiar thing. I need
to upgrade PHP4.0.0 to 4.0.2 (with some extra stuff) and we're running Apache
1.3.12. PHP4.0.0 is a dynamic Apache module and things run fine. When I compile
the new PHP4.0.2, though, stop the webserver and install it over the old
apache/libexec/libphp4.so (by just doing make install in php-4.0.2/ BTW), then
restart the webserver again, none of the webpages work; they all give "Document
contains no data". Yeah, you guessed it, the error_log says a child has
segfaulted. What I don't know, is why and before I need to debug all kinds of
stuff, I wanted to tell you guys this. Anything of this that sounds familiar?
Solutions?

Ivo