In the php 4 spec file, the option '--enable-wddx' to the configure call is not used. This is not a bug, but it makes people who want to use the wddx functions to recompile php. I think there is no reason not to include this option. (The bug is the existance of this option.) Use the function 'wddx_deserialize()' in a php script and you get an error message. If configured with '--enable-wddx', the functions are there.