I have used your suggestion but it hasn't solved yet .
it write in page some character like this :
T?


???
???
???<A\
533;?
0??
&?????ᦙ\
3;@?@?@??????A\
533;n;?????????&#\
65533;?????????&#\
65533;?
&?@>??

but instead, I expect that the download  dialog be open in browser.
I use firefox 3.