About the "comma separated variable"...
I found this information useful when using your method of bulk importing new users in a Moodle 1.1:
"If you live in a country where a comma is used as decimal delimiter rather than the decimal dot (.) in the USA, the CSV file will look like this ...The commas separating the data entries have been replaced by semi-colons (;), and the decimal dots, if any, will be replaced by decimal commas."