Yes it seems you need to set the correct paper size in the print driver for LR's print module to allow you to use it. I have also found that sometimes it fails to correctly change the settings in the driver when using a saved preset, so now I always check the driver settings. This has been with LR4 running under both 32bit Vista, and 64 bit Win 7. I'm not sure if this is an LR or Windows issue, but suspect it is the latter, as I often find that Office applications have picked up LR driver settings, rather than the correct default settings. I do have some LR settings saved in the print driver, a Canon Pixma MG5150.
The other thing I find really annoying is that you can only use paper sizes as specified by a printer driver. Only having an A4 sized printer at home I had to install a Print to PDF driver so that I could set up larger paper sizes, as I usually use the print module to create the files I send out to the lab I use to print at 16×12.