Try to use .deb files for that. http://dev.iron.io/worker/reference/dotworker/#syntax_reference
You need Ubuntu 12.04 x64 packages. Examples:
lots of deb files: https://github.com/thousandsofthem/workers/tree/master/mono-3.0.6
bring-your-own-binary https://github.com/iron-io/iron_worker_examples/tree/master/binary/phantomjs
bring-your-own-binary simple version: https://github.com/thousandsofthem/workers/tree/master/ffmpeg