If you are getting a permission denied error when running the command "chmod 777 /sdcard/3gFix/fix.sh" then you need to make sure your phone's usb connect is set to "charge only". I had mine set to "sd card" so I could copy the 3gFix folder to my phone, and forgot to set it back. The reason you get permission denied is that when your SD card is mounted as a folder in windows or whatever, you will have problems modifying files on the SD card with adb.

On your phone, pull down the notification bar, select "usb connection" and select "charge only". Then unplug your phone from the usb jack, wait a bit, plug it back in.

Even with that, I still had to execute the script line by line. Just open the file "fix.sh" in notepad or notepad++ or any text editor. then type:
adb shell
su
and then paste in each line of the script, starting with the "mount..." line. (Right-click and choose "paste" in the windows command prompt.)