Try using this code, I altered how it waits. See below for more information.

Simba Code:
procedure burnLogs();
begin
typebyte(vk_1);
wait(randomRange(2000, 3000));
toolScreen.select('Tinderbox');
tabBackpack.waitForShift(randomRange(2500, 5000));
typebyte(vk_1);
wait(randomRange(2000, 3000));
toolScreen.select('Add to bonfire');
mouseOffClient(OFF_CLIENT_RANDOM);
repeat //Repeats a small wait(a)
wait(gaussRangeInt(10, 100)); //this is (a)
until (not tabBackpack.waitForShift(randomRange(7500, 10000))); //until there hasn't been a change in backpack count for 2-3 seconds
stats_IncVariable('23', 28);
stats_IncVariable('79', 28 * 50);
stats_commit();
end;
Reason for edit: Faster XP 
Simba Code:
procedure burnLogs();
begin
tabBackPack.mouseSlot(1, MOUSE_RIGHT);
wait(randomRange(2000, 3000));
{if chooseOption.isOpen(gaussRangeInt(2000, 3000)) then //waits between x and y until its open
chooseOption.select(['//text']); } //selects option with x text
tabBackpack.waitForShift(randomRange(2500, 5000));
tabBackPack.mouseSlot(2, MOUSE_RIGHT);
wait(randomRange(2000, 3000));
{if chooseOption.isOpen(gaussRangeInt(2000, 3000)) then //waits between x and y until its open
chooseOption.select(['//text']); } //selects option with x text
mouseOffClient(OFF_CLIENT_RANDOM);
repeat
wait(gaussRangeInt(10, 100));
until (not tabBackpack.waitForShift(randomRange(2000, 3000)));
stats_IncVariable('23', 28);
stats_IncVariable('79', 28 * 50);
stats_commit();
end;