Sorry all......I still have not been able to replicate this. I have 1st gen Zune 30GB...purchased on Black Friday November 2006....with about 10GB of space available. My only thought is I think the 2nd firmware update took care of freezing and skipping issues the early Zune had....since then I have never had any skipping or regular freezing on my device. Occasionally it will freeze on playing but once the HDD catches up it is fine...maybe once or twice a month....I can't remember the last time it happened tho.
One suggestion is to reformat your device to include removing the firmware and then re-installing it.......just remember if you do this it removes ALL CONTENT from your device and you have to sync everything onto it again. Maybe your device has a corrupted firmware update somehow....no clue all!!??
Zune is AWESOME!!...since Nov 2006 Black30GB and Pink30GB (my wifes'!!!)