Google Calendar ical import failure

I can't seem to import my ical feed in Google Calendar (by url) due to the fact that the first lines of the ical file are as follows:

	BEGIN:VCALENDAR
VERSION:2.0
METHOD:PUBLISH

When I download the ical file, remove the tab at the beginning of the first line and import the events from file in Google Calendar, all works fine.

Does anyone else observe this behavior?
Any clue where this tab is printed and how to correct this?

Thanks