Just delete the Arduino 1.0.3 / 1.0.4 folder, and re-download it. But I don't think it has anything to do with the software, I think you need to update your drivers in Device Manager > (that particular COM port for your arduino)
You can try to re-download the software and then update the driver.
Usually when I got that error, it was because I had my Bluetooth module still plugged into the TX/RX pins. Once I removed it, I was able to upload my sketchs.