MACROMEDIA FLEX-FLEX ACTIONSCRIPT LANGUAGE Reference page 426

If you load external text files that are not Unicode-encoded, you should set
System.useCodepage
to . Add the following code as the first line of code in the SWF file that is loading the data:
true
System.useCodepage = true;
When this code is present, Flash Player interprets external text using the traditional code page of
the operating system running Flash Player. This is generally CP1252 for an English Windows
operating system and Shift-JIS for a Japanese operating system.
If you set to , remember that the traditional code page of the
System.useCodepage true
operating system running the player must include the characters used in your external text file in
order for the text to display. For example, if you load an external text file that contains Chinese
characters, those characters cannot display on a system that uses the CP1252 code page because
that code page does not include Chinese characters.
To ensure that users on all platforms can view external text files used in your SWF files, you
should encode all external text files as Unicode and leave set to by
System.useCodepage false
default. This way, Flash Player interprets the text as Unicode.
426 Chapter 6: ActionScript Core Classes