given($LineTemp[1])                        # check the list format
{
    when 0
    {
        for($i = 0; $i <= $#ListData; $i++)
        {
        print "a";
        }
    }
    default
    {
        die "Error: Improper value for list format.  Only 0-4 are valid.";
    }
}

Number found where operator expected at line 3, near "when 0"
	(Do you need to predeclare when?)
syntax error at line 2, near ")                        # check the list format
{"
syntax error at line 6, near "++)
        "
Execution aborted due to compilation errors.