Using 5.1 under linux (glibc 2.4) I have tried several .molden files from the "put,molden" command in molpro 2006.1. I opened these files (one was c2h5, so I'm pretty sure the Molden one's are correct) using Molden 4.4 and everything looks fine. When I open the same files using Molekel the orbitals aren't even close to those I get in Molden. I tried both regular orbitals and localized ones using the Pipek-Mezey method, and both sets differ from those Molden shows.