problems with php and mod_rewrite

When Apache starts I get the message
"PHP startup: unable to load the dynamic library: 'c:\program files\php
\ext\php_exif.dll' - The specified module could not be found."

Also I want to enable mod_rewrite, as per cakephp manual, with the
lines

LoadModule rewrite_module modules/mod_rewrite.so
# these line cause an error :
libexec/httpd/mod_rewrite.so
AddModule mod_rewrite.c

...but apache is unable to restart with the last two lines uncommented.

How do I enable mod_rewrite for cakephp ?

Thanks.