Comment 4 for bug 385927

You can simply create an empty file .cpio.gz (for example test.cpio.gz) and try to double click on it.
You can make another test with an empty file .gz (for example test.gz) and try to double click on it.
You will see that with the .cpio.gz file you will obtain the error while with the .gz file all works ok.

If you want a real test you can download every .cpio.gz file from the web (for example try the following http://www.openmamba.org/pub/openmamba/devel/media/bootusb/it/openmamba-bootusb-it-snapshot-20090801.i586.cpio.gz )