The problem you are experiencing is with this piece of code:
int percent = (totalDataRead * 100) / filesize;
Download.status.setText(totalDataRead / 1024 + "kb/" + filesize / 1024 + "kb");
setProgress(percent);
Your value for percent must be outside the range 0…100 as the exception message is coming from the setProgress method:
http://docs.oracle.com/javase/7/docs/api/javax/swing/SwingWorker.html#setProgress(int)
Note:
IllegalArgumentException – is value not from 0 to 100
solved Java Value must Be Between 0 and 100