Hi, thanks for reporting.
It seems you’re using Safari 5, but if you google for “cannot decode raw data” you will see a lot of people reporting this problem, even on flickr.com https://discussions.apple.com/thread/1226486?tstart=0, and a lot of other sites.
From what I could read, this is due to server configurations, namely gzip being enabled.
For example, this happens on w3 total cache too https://www.ads-software.com/support/topic/cannot-decode-raw-data-in-safari-5?replies=3 and you can see the user solved it by disabling gzip on the server.
Another possible way to confirm this is to use another browser like google chrome and see if the errors show up there or not.
Also from what I read, it seems that Safari 6 may have fixed this bug and doesn’t show this error anymore.
Also did you try on some other device with Windows, Linux or some other browser and did the problems remain?
What seems to happen is that the minification script takes some time to merge and minify your files on your server (could be a slow shared hosting server or a server misconfiguration) and Safari seems to try to download the site while it’s still generating the files, leading to an “incomplete data” message (that’s what it means “cannot decode raw data”, because Safari thinks that whatever they downloaded so far must be gzip encoded).
Either way, it seems to be more of the realm of server administration than due to the plugin, but let me know if you have this error with other browsers and devices and provide me with the url so I can have a look.
