problem with fixed variables in MCSim v5

We just ffound a bug in the way MCSim v5 handles variables set to given
numerical values in MCMC runs:

If you try to do:

Level {

  SD_alpha = 1;

  Level {

    Distrib (alpha, Normal,  0,  SD_alpha);

etc...

you will get an error because SD_alpha in the Distrib statement is set
at zero rather than the prescibed 1.
Even the default value given in the model file is not used...

To correct this you should do: 

Level {

  Level {

   Distrib (alpha, Normal,  0,  1);

etc...

or