SpoonWEP is basically a graphical frontend, and a very nice one I might add, for the aircrack-ng suite, which pretty much is the best tool for cracking WEP/WPA encryption out there. As the size of the packets can vary a great deal it is the number of IVS that you need to look at, how many have you collected so far? Chances are that you need to collect more to be able to crack the key, as a 128 bit key should not take that long to find using enough IVS.



