rlm_ruby

Good Day I am having problems using the rlm_ruby module. When starting radiusd I get the following error: radiusd: symbol lookup error: /lib/rlm_ruby-2.1.6.so: undefined symbol: ruby_init I have ruby 1.8.7 installed from source on CentOS 5.2 If anyone could give me a few pointers as to what I could check on the settings I would appreciate it. Thanks Werner Stucky