I've looked through iwconfig again. There is a high invalid crypt rate.
Link Quality=100/100 Signal level=-30 dBm Noise level=-87
dBm
Rx invalid nwid:0 Rx invalid crypt:42 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:60 Missed beacon:0

#man iwconfig says invalid crypt

Rx invalid crypt
Number of packets that the hardware was unable to
decrypt. This can be used
to detect invalid encryption settings

It seems that WEP has gone wrong. ( i think so) I've already convert
the ascii to hex via
http://www.funchords.com/ascii2hex/