Android - I modified vold.fstab and lost access to my SD card
I don't know about Android Commander, but a simpler way (in my opinion) would be to use ADB. You may have already installed the Android SDK (if not, go here). I assume that you don't have modified your System Path.


Move your vold.fstab to C:\Program Files\Android\android-sdk\platform-tools or C:\Program Files (x86)\Android\android-sdk\platform-tools
Go to the android-sdk folder, shift+right click on platform-tools and choose "Open command prompt here"
If your device is 4.0 or above, type adb root
adb remount (this will make /system writable)
adb push vold.fstab /system
adb reboot


This should do the trick.