I think this might be related to your browser, since when I try to subscribe to your RSS and Atom feed with FireFox 10.0.4 on Scientific Linux 6.4, I get redirected to Google Reader, so it works for me.
Your atom feed also tries to download the file on my computer. Firefox 14.01 on Kubuntu. The RSS2.0 feed seems to work correctly here. This might be something that changed in Firefox after version 10.x. During my testing, I also got several 500 Internal Server Error pages.
I notice your RSS1.0 feed seems to be missing <?xml version="1.0" encoding="UTF-8"?>
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I notice your RSS1.0 feed seems to be missing <?xml version="1.0" encoding="UTF-8"?>