We have 1006z>2011y>2011, hence z≥2. Then 1005x+2011y≡0(mod4).
But 1005x≡1(mod4), so 2011y≡−1(mod4)⇒y is odd, i.e. 2011y≡−1(mod1006).
Since 1005x+2011y≡0(mod1006), we get 1005x≡1(mod1006)⇒x is even.
Now 1005x≡1(mod8) and 2011y≡3(mod8), hence 1006z≡4(mod8)⇒z=2.
It follows that y<2⇒y=1 and x=2. The solution is (x,y,z)=(2,1,2).