It's quite possible given the age of the software that iphoto '09 simply hasn't been updated to be fully compatible with newer versions of raw files and dng conversions of them and especially any lens correction data built in to them. In respect to a converted dng file it's also possible that there is an NIH (not invented here) attitude being applied here through the Apple software to the Adobe file format. I don't know much about Picasa, I'm afraid.
There are various approached applied by raw converter softwares to lens correction. Some like Adobe apply the manufacturer supplied data with no option to turn it off. DxO ignores it and creates their own, and others seem to allow it to be turned on or off.