With all due respect, I believe your answer to the lady who had this problem was completely wrong. You advised her to lower the humidity in her basement where the dryer is located. But the dryer is closed to ambient air when the door is closed so the moisture probably is due to high humidity air leaking into the dryer from the outside air vent. The air is not circulated away by the A/C (again - closed system). This humid air condenses and puddles in the dryer drum.
I have this problem (as well as many others based on web posts).
How to fix it? Don't know but I think putting a flapper in the vent line where it enters the outside wall and another flapper where it leaves the outside might. This should greatly decrease the flow of outside air into the dryer when it is idle.
What do you think? Any ideas? Sorry for the long question.