can someone explain this error plz?
 

when iam trying to configure wireless under root i get this:
[root@localhost markymark]# iwconfig eth0 key off
Error for wireless request "Set Encode" (8B2A) :
SET failed on device eth0 ; Operation not supported.

anything i do related to
iwconfig eth0 something something

i get the error.
anyone know why this is happening?

Is eth0 a wireless eithernet adapter? What driver are you using for your wireless card? Does it work if you do an ifconfig eth0 up first?

iam not really sure work eth0 is, but its most likley adaptor
iam using belkin adaptor

sorry it does work with ifconfig eth0, i get this:
Link encap:Ethernet HWaddr 00:05:5D:FD:D2:A7
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
Interrupt:19 Base address:0xec00

any idea?

Have you installed the wireless tools?

yep