Mod_dav Build

Hi Greg,
I build mod_dav-1.0.2-1.3.6 with Apache_1.3.14
I used the ./configure --with-apxs=/usr/local/apache/bin/apxs 
make
make install

seems to be o.k. 
But when I run start apache I got "Can't load
/usr/local/apache/libexec/libdav.so into server : undefined symbol:
XML_SetElementHandler"
The file libdav.so does exist.

Any body can explain why? 

Thanks

PC Wang