Trouble with state-machine

Hello,

I'm trying to build a state-machine in AHDL using Quartus 2 v7.2. During compilation I get these messages:

Warning (14130): Reduced register "..." with stuck clock port to stuck value GND

Warning (14110): No clock transition on "..." register due to stuck clock or clock enable

Later in compilation, I get this message, telling me that the output of the state-machine is at ground:

Info: Pin AT has GND driving its datain port

Here is a state-machine like I programmed, I must have made some terrible mistakes. Can tell whose?

SUBDESIGN state_machine2

(

s[2..0] : INPUT;

Takt0 : INPUT; %clock%

AT : OUTPUT;

)

VARIABLE

AT : dff;

M1 : MACHINE WITH STATES (zero, one, two);

BEGIN

AT.clk = Takt0;

M1.clk = Takt0;

CASE M1 IS

WHEN zero =>

AT = B"0";

IF (s[] == 1) THEN

M1 = one;

ELSIF (s[] == 2) THEN

M1 = two;

ELSE M1 = zero;

END IF;

WHEN one =>

AT = B"1";

IF (s[]==1) THEN

M1 = one;

ELSIF (s[]==2) THEN

M1 = two;

ELSE M1 = zero;

END IF;

WHEN two =>

AT = B"0";

IF (s[]==1) THEN

M1 = one;

ELSIF (s[]==2) THEN

M1 = two;

ELSE M1 = zero;

END IF;

WHEN others =>

M1 = zero;

END CASE;

END;