What do you think was happening?
Seems like some kind of bilinear interpolation is being applied to the blitted text but i can't find a reason for this behaviour nor can i reproduce it. I've tried to blit your texture and parts of it on 3 different systems down to a PII-400/Linux/GF2-MX machine and the blitting looked just fine on all of them.
Is this gif that you've posted exactly the same file that you are using for blitting?
Another try: Can you please check out if setting Config.glFixedBlitting=false; changes anything? In either case, can you provide me with a simple test case that shows the problem on your machine? As said, i can't reproduce it here but without knowing exactly what you are doing, i can't tell if it's my fault or yours or whoever...