On a ubuntu server, with everything installed (checked against another pc where this works just fine) When trying to run warble on one of my jruby projects, I get this error:

Function 'xmlFirstElementChild' not found in [libexslt.so]
/opt/jruby-1.5.0/lib/ruby/site_ruby/shared/ffi/ffi.rb:112:in `create_invoker'
/opt/jruby-1.5.0/lib/ruby/site_ruby/shared/ffi/library.rb:98:in `attach_function'
/opt/jruby-1.5.0/lib/ruby/site_ruby/shared/ffi/library.rb:96:in `each'
/opt/jruby-1.5.0/lib/ruby/site_ruby/shared/ffi/library.rb:96:in `attach_function'
/opt/jruby-1.5.0/lib/ruby/gems/1.8/gems/nokogiri-1.4.2-java/lib/nokogiri/ffi/libxml.rb:116
/opt/jruby-1.5.0/lib/ruby/gems/1.8/gems/nokogiri-1.4.2-java/lib/nokogiri/ffi/libxml.rb:31:in `require'
/opt/jruby-1.5.0/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `require'
/opt/jruby-1.5.0/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:156:in `require'
/opt/jruby-1.5.0/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:521:in `new_constants_in'
/opt/jruby-1.5.0/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:156:in `require' 
/opt/jruby-1.5.0/lib/ruby/gems/1.8/gems/nokogiri-1.4.2-java/lib/nokogiri.rb:11
/opt/jruby-1.5.0/lib/ruby/gems/1.8/gems/nokogiri-1.4.2-java/lib/nokogiri.rb:36:in `require'/
/opt/jruby-1.5.0/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:36:in `require'
/opt/jruby-1.5.0/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:156:in `require'
/opt/jruby-1.5.0/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:521:in `new_constants_in'
/opt/jruby-1.5.0/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:156:in `require'
[...]

all libraries and required gems seem to be there. Google didn't help, and the strange thing is that on other pc this works fine...

danilo