Yes, I tried doing just a simple sketch. Like I said, I uninstalled the arduino software and all extra libraries (in the documents fold on both mac and windows). I then just tried the blink led sketch, on both windows and mac. It uploads fine on windows, but on the mac side I get the error.
The GPS shield is not using pins 0 and 1 when it is on the arudino as I can upload fine on windows.
Yes, I did search. But as you said it has come up a lot lately so there are a lot of searched to sift through. None of what I read seems to be the appropriate answer. Most are saying the cable/ftdi connection is bad or the wrong board was selected. If either of those were the case it wouldn't work on the windows side.
So, the conclusion then is somehow the Mac side has decided to not like the FTDI cable anymore. I have an RBBB arduino on the way, I will have to try with that when I get it. I have this cable: http://www.sparkfun.com/products/9718
I did notice when double checking the board to select in the software the two Arduino Pro entries are the same description. They both say the 128 version. No 328 version listed. I tried all possible 328 boards. As I said, it worked a couple weeks ago but not now. I don't remember what board was selected a couple weeks ago.