Undefined symbol: rb_defout when loading mod_ruby

Hi all,
When I try to start Apache (1.3.29 on Linux) with the mod_ruby (1.1.3) module, I get the following:

Syntax error on line 60 of /etc/apache/conf/apache.conf:
Cannot load /etc/apache/extramodules/mod_ruby.so into server: etc/apache/extramodules/mod_ruby.so: undefined symbol: rb_defout

I know I've seen this before, but I can't remember what I did to fix it. Can anyone enlighten me?

Tim.

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Tim Bates
tim@bates.id.au

Syntax error on line 60 of /etc/apache/conf/apache.conf:
Cannot load /etc/apache/extramodules/mod_ruby.so into server:
etc/apache/extramodules/mod_ruby.so: undefined symbol: rb_defout

Well, one possibility : It's compiled with 1.6.8 but run by 1.8.1, no ?

Guy Decoux