Weird runtime error while implementing a bubble sort in Pascal

This snippet not only causes a runtime error, it makes FPC close if I run it using the debugger.

procedure sortplayersbyscore(var vAux:tplayers);

    procedure swap(var a:trplayers;var b:trplayers);

    var
        rAux:trplayers;

    begin
        rAux:=a;
        a:=b;
        b:=rAux;
    end;

var
    i,j:integer;
    sorted:boolean;

begin
    vAux:=playersarray;
    i:=1;
    sorted:=false;
    while (i <= MAXPLAYERS -1) and not sorted do
    begin
        j:=1;
        sorted:=true;
        while (j <= MAXPLAYERS -i) do
        begin
            if (vAux[j].score < vAux[j+1].score) then
            begin
                swap(vAux[j],vAux[j+1]);
                sorted:=false;
            end;
            inc(j);
        end;
        inc(i);
    end;
end;

The code itself is part of a really big source file, I can post the whole thing but the responsible for the error is just that bunch of lines. The debugger terminates at line:

swap(vAux[j],vAux[j+1]);

tplayers is just a type defined as an array of records that contain score (an integer) among a bunch of other variables. trplayers is the type of the aforementioned records. I'm at a total loss; FPC (while 开发者_如何学编程not under debugging mode) spits an out-of-range error but under my watches I see that the variables I'm trying to read exist. Any help is really appreciated!

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rAux:trplayers; have you typed a wrong symbol or the type here really contains "r" in its name?

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It looks valid (other than typos) ... so let's try something simple.
What's the value of "j" when you abort? If the debugger won't tell you, try adding:

writeln ('j = ', j);

just before the "swap" call.

As Yochai's question implied, your array needs to be dimensioned at least from 1 (or lower) to MAXPLAYERS (or larger). (I.e.: 0..MAXPLAYERS-1 would not work, but 1..MAXPLAYERS should.)