为什么会运行时错误？哪位大神来帮我看一下！

var ch:char;
    g,t:longint;
    a:array[1..1000]of char;
  procedure try(k:longint);
    var l,w:longint;
    begin
      w:=0;
      l:=0;
      while (a[g]<>'E')and(g<=t) do
        begin
          if a[g]='W' then inc(w)
                      else inc(l);
          if ((w>=k)or(l>=k))and(abs(w-l)>=2) then
            begin
              writeln(w,':',l);
              w:=0;
              l:=0;        
            end;
          inc(g);                                                         
        end;
      writeln(w,':',l);
    end;
begin
  read(ch);
  while ch<>'E' do 
    begin
      while (ch<>'W')and(ch<>'L')and(ch<>'E') do read(ch);
      if ch<>'E' then 
        begin
          inc(t);
          a[t]:=ch;
          read(ch);
        end;  
    end;  
  g:=1;
  try(11);
  writeln;
  g:=1;
  try(21);
end.