hi,
 

First :
    we get a lot of cliking
    where do you think it come from [lame ?]

first, i suspect some bandwidth problems.
lame is not that CPU-intensive
but you can check this with a 'top' command
( check CPU status ).
 
to find the bottleneck,
several actions might be taken :
 
a/ emit your stream towards a machine on your LAN,
do clicks still happen ??
 
b/ lower mpeg quality until clicks disappear.
especially, lower bitrate and increase quality factor
( higher quality parameters are LOWER quality in fact ).
let's try : "mpeg 8000 8 2 9"
which is the lowest quality.
 
also, check that pd is running with the -rt flag.
 
let me know the results of all these actions.
 
Yves/
 
PS : i've never tested shoutcast on the net, only on a LAN.
no noticeable clicks.