AHDL program: HELP!

I know this is a VHDL group, however, since there is no AHDL group and
I read more than one post in which people talked about using or having
used AHDL I suppose I can find some help in here.
This is the code:

SUBDESIGN FlipD
(
D,LE,CL,PS :INPUT;
Q :OUTPUT;
)

VARIABLE
tmp[1..0] :NODE; %store latches outputs%
en,out :NODE; %Enable of slave latch and master-latch output%
%prep[1..0] :NODE; %Array of preparatory states%

BEGIN

tmp[0]=out; %copies MASTER-output%
tmp[1]=Q; %copies SLAVE-output%
en=!LE; %SLAVE latch-enable (negation of LE)%
prep[]=(PS,CL);

IF(LE==VCC) THEN %Latch-Enable on%

CASE prep[] IS
WHEN b"01"=>% CL activated, out goes to GND%
out=GND;
WHEN b"10"=>%PS activated, out goes to VCC%
out=VCC;
WHEN OTHERS=>%any other combination: transparent latch%
out=D;

END CASE;
END IF;
ELSE
out=tmp[0]; %MASTER-output remains the same%
END IF;

IF(en==VCC) THEN %if slave is enabled%
Q=out; %update output value by copying MASTER output%
ELSE
Q=tmp[1];%SLAVE output remains the same%
END IF;
END;

What I'm trying to do with this code is a D type Flip-Flop. The funny
thing is that if I remove the CASE block (which analices CL and PS
inputs), the thing works just right, but when I try to simulate the
whole program (with CL and PS set in any different values, it doesn't
make a difference) the output gets stucked at VCC forever.
Any ideas?