load and save files for mobile and desktop

I saved a file in a similar way(File.desktopDirectory.resolvePath("test.txt")) because I couldn't figure out how save a file in my swf folder that gets uploaded to to the android.  Now I tried to access the file this way but i get

Error: Error #2030: End of file was encountered. at flash.filesystem::FileStream/readUTF()

var myFile:File = File.desktopDirectory.resolvePath("test.txt");

var fileStream = new FileStream();

fileStream.open(myFile, FileMode.READ);

//the file is not gone

var fileText:String = fileStream.readUTF();

fileStream.close();

trace(fileText)

I have used   URLRequest = new URLRequest("test.txt")  but I dont know how to get to the document folder that way and I dont know if a path would work for android and computer

maybe sharedObject is the better way to go for storing data but I am more comfortable using xml files

I have spent hours on this that is just the latest attempt