I just downloaded and installed. Ran into the same issue: the pages and information were in German. I was able to switch the language to English, though, and these steps may work for you too.
To see the English version I performed the following steps:
Downloaded and installed AudioGrabber. I have Win 7, 32-bit.
Ran AudioGrabber as installed. Saw German menus and icons.
In the menu area, I click on the first choice: Datei.
In the resulting menu, I selected Sprachauswahl and opened its submenu.
In the submenu, I chose English (default). At that point, the application switched to showing English.
That was it for me. I closed AudioGrabber, restarted it, and saw everything in English. Hope this helps.