Arduino Fio, FTDIUSBSerialdriver fails to create Serial Port on Mac OS 10.8

Dear You,

After browsing links concerning my problem with my Serial Port on an Arduino Fio and tailing down the troubleshooting pipe lines, I am wondering if someone else has experienced similar issues on Mac OS 10.8.5 Mountain Lion, using FTDIUSBSerialDriver. I've gone thru the process of deleting and installing the drivers a few times, advertantly also trying not only FTDI but Prolific as well, only with the result, that if I connect my Arduino Uno, I get a Serial Port with cd /dev, ls -l using Terminal:

crw-rw-rw-  1 root       wheel      18,   0 28 Mär 13:26 tty.usbmodem1421

In other words, the Uno is running fine and seems to upload my blink sketch, whereas, with the Fio, the above tty.usbmodem1421 disappears and is no longer available. I have selected the right Boards, furthermore, I checked if the problem could be related to the bootloader, but since it is blinking on manually resetting the Fio, I think my problem not to be able to upload the sketch from the IDE to the Fio, is due to the missing Serial Port, here refered to as usbmodem. What I'm not sure about, is the correct Baud Rate for the Fio (9600 ?), but I assume, that as long as there is no Serial Port, that is not an issue either. 1. My FTDIUSBSerialDriver.kext, is properly installed in the /System/Library/Extensions Folder.

  1. I have currently the Arduino IDE 1.0.5 installed. I read about an upgrade of the IDE to current Version 1.5.5-Beta, though cannot find download links for Mac OS 10.8, does anyone know, whether this might bring about a change with my Serial Port Problem on the Fio?

  2. Essentially the Error I get in the IDE when uploading the Sketch is: avrdude: stk500_recv():programmer not responding, so I looked up this thread in the Forum quite a bit, but to no avail, for instance someones blog suggested rebuilding avrdude from scratch, but it was on a much older Mac OS (10.4.), so I didn't not attempt to do it.

If anyone might have a clue, how to proceed from here, that would be very helpful, because I seem to be running in circles. Thank you upfront for your time and concern.