module load error apr_sockaddr_get

Hello,
I'm trying to get mono and mod_mono going with apache 2.2.3. I've got it
all installed, but when i run a configtest i get an undefined symbol error:
undefined symbol apr_sockaddr_get. The apache version is 2.2.3-7 on CentOS5
installed from rpm, and mod_mono 1.2.4 rpm downloaded from www.go-mono.com.
If anyone has a fix for this error i'd appreciate knowing about it.
Thanks.
Dave.