Encoding UTF-16 requires that a BOM be provided in the data to decode to determine whether UTF-16le or UTF-16be was used. The error you are getting is the error that is generated when the first character is not a UTF-16le or UTF-16be BOM character.

To decode UTF-16le data without a leading BOM, specify UTF-16le as the charset.
To decode UTF-16be data without a leading BOM, specify UTF-16be as the charset.

Update: Nevermind. That's not the error message given by the case I've explained.