Alt key in woody

[Wu XiaoGuang]

Hi, all:
  I just installed Debian GNU/Linux 3.0 . The GNU Emacs version is
  21.2 .
  I couldn't use Alt key normally. Although I could use it it in
  terminal (emacs -nw), it's a little unsuitable.
  I tried to put 
,----
| xmodmap -e "keysym Alt_L = Meta_L Alt_L" & 
`----
  in ~/.xinitrc or ~/.xsession , but after I do this, I can't startx
  later.

  Thank you.