It's like your user says: In Swedish thousand separator is white space " " and decimal separator is comma "," and currency symbol "kr" (Krona). So colon ":" is definitely wrong.
You can check it here too: http://www.localeplanet.com/java/sv-SE/
What Java version are you using? It works well on my desktop 1.6.0_13
-- update --
It seems that on Android there's a bug, but you can go around the bug by using the DecimalFormatSymbols like this:
DecimalFormat svSE = new DecimalFormat("#,###.00");
DecimalFormatSymbols symbols = new DecimalFormatSymbols(new Locale("sv", "SE"));
symbols.setDecimalSeparator(',');
symbols.setGroupingSeparator(' ');
svSE.setDecimalFormatSymbols(symbols);
This prints the correct separators in Android as well.