I thought i would try this option estimating a simple model (always the best way to gain experience and confidence with the routine).

Independent variable, 1 indep variable  . No lag on Y. . Zero selected for out of sample forecast   Constant -can be omitted.   Best 4 models selected -again as the default.

This was the output:-

Dependent viariable was removed from the X list. It is not there -there is only a single indep variable.
Error message from BACE_GUI():
 Average model size should be greater then 0 and lower than K !!!   Average model size specified is the default 1