Maven Problem! Plugins And Sh1t?!?!!?

This Happens When I Try To Compile With Maven.

Basically When I Reach Where i Have To Right This :

C:/maven/bin/mvn assembly:assembly -Dmaven.test.skip=true" <enter>

i got that error.. i asked for help but none helped me ( in msn ! xD ) tHey didnt knew what that was..

So im asking if u know ^_^

Plx Help Me.