I found a solution thanks to this web site:
Translate it with google translate to english. I had some problems installing the right driver on my windows 7 x64 machine but I succeeded.
Basically it goes like this:
1. Download the zip from the link on the web page and unpack it.
2. Start the RKAndroidTool.exe (in the status bar it will say "No found RKAndroid rock usb")
3. Shut down your tablet and disconect the usb cable from the tablet that is connected to your pc.
4. Press the volume up button and hold it for 6 - 7 secconds.
5. Still holding the volume up button plug in the usb cable that is connected to You pc. (At this point in my case nothing happened)
6. (If nothing happens) Go to control panel - device manager and there You will see an unknown device.
7. Right click on the unknown device and select update driver. Point to the folder where You unpacked the downloaded zip / Drivers folder and select the search in subfolders checkbox. press OK button. Windows will install the drivers. After that if the tablet didn't start automatically boot it up by pressing the power button.
8. The RKAndroidTool.exe now will recognize the device.
9. Set the checkbox next to rom/recovery.img and press "RUN"
10. The tool will do what it has to do.
From here on just follow the instructions for rooting the tablet from the website.
Hope it will work for You as it worked for me.