Ok, i dont use 1.28, so im not sure, but please check the unit used, is it kb (kbits) or kB (kBytes) on amule?
The diference is important since 1 (B) byte = 8 (b) bits, so your limits should be download=32/upload=16 (256/8 - 126/8).
100 clients is an abnormal behavior with most connections, so i guess you have your values wrong.
EDIT: also, dont put your upload limit equal to your upload capacity (consider 14, not 16, in ADSL), or you will choke your connection, put it 2kB lower, at 12 kB max.