How to root Acer Iconia A100?

I am having trouble trying to root my Acer Iconia A100 with Android 4.0.3. I have tried several rooting methods and they always fail.

I have the USB debugging enabled, and all the adblock or antivirus apps are off.

I've tried all of these:

• SRSRoot


• KingoRoot


• KingRoot


• Z4root


• How to Root Acer Iconia A100 Tablet

Am I just missing a step somewhere?

Here is the report from the SRSroot app:

---= SRS One-Click-Root v5.1 =---



11:29:11 AM - Starting ADB Server..

11:29:16 AM - Manufacturer: Acer

11:29:16 AM - Model: A100

11:29:16 AM - Android Version: 4.0.3

11:29:16 AM - Build ID: Acer_AV041_A100_1.049.00_PA_CUS1

11:29:16 AM - Board ID: vangogh

11:29:16 AM - Chipset Platform: tegra

11:29:16 AM - Getting OffSets.. : 0xd9f0 0xaf47 (True) 

11:29:17 AM - Query Server for Best Method.. Found Rootkit: 4




 ----= Start Rooting Process.. Please Wait =----



11:29:17 AM [+] Testing exploit: root8 (please wait..)

11:29:39 AM [+] Executing root8 exploit Failed. 



11:29:39 AM Auto Root Failed on this device. :( 



11:29:39 AM Rebooting Device and try again... 

On the Kingo, when I run the Windows application to root the Android it always says that rooting was successful, but when I try to do anything that requires root (like installing busybox) on the Android, it always fails. Then when I restart the android the rooting is gone.

So, I can root it with Kingo, and if I use SRSRoot after that, it says the android is, indeed rooted, but it doesn't persist. When I reboot the Android then run the SRSrootkit then it sees that the Android is not rooted (even though it seemed to be before reboot) and it cannot root it itself.

Using the unlockr method, I find that the batch file reports mkdir failed for /data/local/tools, permission denied with subsequent permissions errors. And so that method is not able to get root either.