@jamesh. Thanks for contacting me. I tried downloading one of the files, and it showed fine to me. There was no message of corruption when I opened the files. I tried it in two environments: Safari on Mac OS X, and Chrome on Windows 7. Here is the screenshot of it open on my Mac.
Also, typically, if the extension works normally on all your servers except one, then maybe the issue is that particular server. However, from my test, it works fine for me. Could you elaborate on the problem on your end when you say the files are corrupted? So far, from what i can tell, it is working as expected.