Sounds like there is a little flaw towards the end of the audio which makes it sound like szombatron. Hmm... Samba-tron?
"On Thursday, on Friday or on Saturday?" - this is not good?
No, this is fine, although a bit unusual in English. Please report it. :)
On Thursday, Friday, or on Saturday. Marked wrong. What is wrong with it?
Ray, you should either use "on" only with the first item, or with all items. You're making a weird mix here.