abi>>forums - File Handling Help

I have a couple of questions on file handling. The first is can anyone tell me why I am getting this error:

Quote:

20: bad argument #1 to 'read' (invalid format)

for this code:

Code:

function collision(file,p,mapmax)

     local collisiontable={};

    Collisionmap = io.open(file,"r");

    if p.lr == "left" then

        Collisionmap:seek("set",p.x);

    else

        Collisionmap:seek("set",p.x+p.maxx);    

    end

    for i=1,28 do

        table.insert(collisiontable,{});

        collisiontable[#collisiontable].type = Collisionmap:read("*n");

        Collisionmap:seek("cur",mapmax);

    end

    io.close(Collisionmap);

    return collisiontable

end

This was working before but now I do not know why it crashes ("*n") is a proper format.

Second question, i am trying to create a temporary file and this works to an extent:

Code:

tmpcol = assert(io.tmpfile())

tmpcol:close();

If you are wondering why assert is there it is because without assert it prints out the error:

Quote:

tmpcol is a nil value

if you put it there:

Quote:

Permission is denied

This happens with the adk, if you do not run as administrator ( vista/windows 7).

Does anyone know of a better way to create a temporary file?