Every time you get a syntax error is because you ar calling on the application option wrong. IE:
aircrack-ng [options] <capture file(s)>
Thats almost standard in Linux...
The other thing I can think of is that the command is not supported in aircrack... If I am not mistaken people is been having problems with aircrack-ng
can sum1 tell me y i get dis please
aircrack loads fine but wen i wanna brute frce or run command like a <amode> iget da error