In an interview with German magazine Spiegel online, the Austrian Chancellor Werner Faymann has effectively admitted that his country never held a referendum on the Lisbon Treaty because they knew that people would vote no.
No doubt this is precisely why none of the others (except Ireland) did either:
"The fact that we only ratified the new EU Constitution and then the Lisbon Treaty in our parliament is not exactly glowing proof that we were confident that we had popular approval. And now, if we are asked to vote a third time because the Irish will perhaps vote no once again, then we cannot claim that this is what a parliament is authorized to do. It's a matter of style, as far as I am concerned."