I just had this problem last night and was looking for a solution today. I am also using Windows XP with Apache 2.0.40 and PHP4.2.2.
I have tried modifying the line with forward and backward slashes, moving the file to new locations, and trying a trick somebody suggested. The trick was to change the extension of the .dll to .so. None of these helped at all.
The error message in the console when trying to run Apache from there is the following:
Syntax error on line ###(whatever line I had it on at the time) of C:/Program Files/Apache Group/Apache2/conf/httpd.conf:
Cannot load C:/php/sapi/php4apache2.dll into server: The specified procedure could not be found.
I probably did much like dopecoder there and followed every tutorial and explanation possible for this install. Hopefully there is just something missing, some trick, or perhaps it is a bug not yet documented??
Hope somebody can clear us up 🙂