Ok, now this is an actual issue and not a generic question.
What is the actual error message you got?
At what point does it fail?
Which version are you trying to install?
1066mhz amd does not tell me anything, that could be an old k7, an amd durron/sempron, a newer single or dual core amd e1 type cpu, or anything inbetween. Identifying a cpu by its MHz is like when the car-parts guy asks you the make, model, and engine size of the car you say "a 4 door one".
Linux had limited support for the older AMD processors so that could be your problem, but cant tell you without knowing what Lubuntu version, the error message, and what your cpu actually is.