the difficulty with beating the market currently is the fact that most of the substantial jumps and losses were caused by huge volume swings with no real precursors. There's no good way to predict someone coming along in a slow moving market and in one swoop making a huge purchase/sale. No trend gets established, just BAM, huge change.
the sharper the angle of the upswing or downswing, the harder to 'trend'. the more curvy, the easier.
the shorter your timescale, the more you can see the curve to a mass purchase / sell, but then you also subject yourself to other issues.
tis a balance between looking at big picture, missing finer detail, vs looking in close, seeing details, but also being thrashed by false signals
Is the default trading fee that you're backtesting with the .6% of mtgox? Or are you using 0% commission fee?
If you click on the "settings" tab next to the "log" tab, you will see that the bot defaults to 0.55 trading fee. One step up from the 'base' gox fee.