Are these examples of a continuos stroke or are you stopping the movement and then continuing it?
- You can continue drawing the same
line if you select it previously and
then draw nearby with the brush or
a reason for these breaks might be that you are releasing pressure at a certain point and therefore a new line is started when pressure is incremented again. Resulting in two strokes instead of one.
I too have Windows 7 (you meant x64, right?) and had some trouble with the drivers. Pressure would not be registered in certain programs. I found out that the ink utility (handwriting recognition and on screen writing) generated some sort of conflict with the wacom driver. After deactivating the windows tablet service and reinstalling the wacom drivers this was fixed.
The las thing that occurs to me is that you might accidentally nudge your mouse or activate the trackpad etc?
I have an Intuos 4 and so far have had no problems with continuous strokes. I drew more or less complex drawings completely in Illustrator and have had no problems (after fixing the drivers issue).
//Edit You might also want to have a look at the fidelity and smoothness options available when double-clicking the brush or pen icons