iPrint on OES 11 SP2. Not sure about patch level, sorry. On one Windows 7 Pro SP1 x64 device (fully patched) we can't install printer via iPrint web-page (using IE) requesting iPrint Client to install, but it's installed (6.01). Tried on another (two) W7 devices seems to be ok, auth box appear and ready to go. I know this isn't much info, but maybe there is some quick ideas what to check? (On this device in question we solved problem using command line to get iPrint printer installed.)
More thanks, Alar.