Ваш формат неверный и вот почему
Sun, 15 Jan 2012 17:09:48 +0000
DDD, DD MMM YYYY HH:MM:SS +HHMM
^^^ ^^ ^^^^ ^^ ^^ ^^^^^ < Treating the last 2 digits of the timezone as months
^^^ ^^ ^^^^ ^^ ^^ ^^^ < Treating the first 2 digits of the timezone as hours
^^^ ^^ ^^^^ ^^ ^^ ^ < Hardcoding the + (timezone can handle that)
^^^ ^^ ^^^^ ^^ ^^ < Using fractional seconds (not a big deal)
^^^ ^^ ^^^^ ^^ < Using months instead of minutes
^^^ ^^ ^^^^ < Using weak year instead of calendar year
^^^ ^^ < Using day of year instead of day of the month
^^^ < Using day of year instead of day of the week
Вот правильный формат "EEE, dd MMM yyyy HH:mm:ss ZZZ"