Ringtones - " an unknown error occurred (-50)

[TMass518]

EVerytime I try to make a ringtone on my computer I get " an unknown error occurred (-50). I live in the US; have version 8.2 on my computer, try to do it with only songs I've bought that have the little ringtone bell. BUT no ringtones...then itunes sends me a bill for it even thought it doesn't exist. They just billed me for the same ringtone 11 times. I kept trying to create it. Anyone else haveing this problem???????