I had also problems with that..
I messed around with all stuff.. eventually i went back to earlier version of apache..
Problem stayd.. then i noticed tht in windows system folder there was only php4ts.lib but no dll
I know i messed around with dll's and deleted em and copied and again and again..
but I am sure I had that dll in place when i installed apache2..
so i copied dll again and apache ate my php like old man..
then i uninstalled apache and installed apache2 and voila it worked also..
so i guess some ald win xx tricks just mess around with it a little
Now i hav problem with postgres, it seems php gives a @!#$ about php.ini file and pg_connect is sunknown to it..
nomatter what extension directory i give ..