{$A8,B-,C+,D+,E-,F-,G+,H+,I+,J-,K-,L+,M-,N+,O-,P+,Q+,R+,S-,T-,U-,V+,W-,X+,Y+,Z1}
program Project5;

{$APPTYPE CONSOLE}

uses
  SysUtils;

const cn: array [0..1] of extended=(1,1.414213562373095);
      dx: array [1..8] of integer=(-1,0,1,1,1,0,-1,-1);
      dy: array [1..8] of integer=(-1,-1,-1,0,1,1,1,0);

var a: array [0..76,0..76] of byte;
    i,j,n,m,k,x,y,x1,y1: integer;
    v,s,res: extended;
    ch: char;
    flag: boolean;

  procedure wave(x,y,x1,y1,n,m: integer; var res: extended; var flag: boolean);
  var fl: array [0..76,0..76] of byte;
      r: array [0..76,0..76] of extended;
      och: array [1..6000,1..2] of integer;
      i,j,b,e,xz,yz: integer;
  begin
    flag:=false;
    For i:=1 to n do
      For j:=1 to m do
        begin
        fl[i,j]:=0;
        r[i,j]:=0;
        end;
    b:=1;
    e:=1;
    och[b,1]:=x;
    och[b,2]:=y;
    fl[y,x]:=1;
    while b<=e do
      begin
      If (och[b,1]=x1) and (och[b,2]=y1) then
        begin
        flag:=true;
        break;
        end;
      For i:=1 to 8 do
        begin
        xz:=och[b,1]+dx[i];
        yz:=och[b,2]+dy[i];
        If (a[yz,xz]=0) and (xz>0) and (xz<=m) and (yz>0) and (yz<=n) then
          begin
          If fl[yz,xz]=0 then
            begin
            inc(e);
            och[e,1]:=xz;
            och[e,2]:=yz;
            r[yz,xz]:=r[och[b,2],och[b,1]]+cn[i mod 2];
            fl[yz,xz]:=1;
            end
            else
            If r[yz,xz]>r[och[b,2],och[b,1]]+cn[i mod 2] then
              r[yz,xz]:=r[och[b,2],och[b,1]]+cn[i mod 2];
          end;
        end;
      inc(b);
      end;
    If flag then
      res:=r[y1,x1]
      else
      res:=0;
  end;

begin
  readln(m,n,k,v);
  For i:=1 to n do
    begin
    For j:=1 to m do
      begin
      read(ch);
      If ch='#' then
        a[i,j]:=1
        else
        a[i,j]:=0;
      end;
    readln;
    end;
  s:=0;
  readln(x,y);
  For i:=1 to k do
    begin
    readln(x1,y1);
    wave(x,y,x1,y1,n,m,res,flag);
    If flag then
      begin
      x:=x1;
      y:=y1;
      s:=s+res;
      end;
    end;
  write((s/v):0:2);
end.

AC now

I have wa7 too.
I used dijkstra.
Give me hint, I can't find mistake :(((