Ruby script to convert an Ogre Mesh XML into flower error

i'm using ogre1.7.1+nxogre1.5.5. Ineed some special mesh format,so i use flour. but runtime error everytime.

so i download flour 0.4, but it no longer surpport *.mesh. and betajaen give us the ogrexmltoflower.rb, which is Ruby script
to convert an Ogre Mesh XML into flower, and then convert *.flower to *.nxs.

but I use ruty ogrexmltoflower.rb to convert *.xml to *.flower error.
can anybody kowns that help me.

thanks!