There are many interpretations, some not even about women. Here are two opposing views about women and wisdom.
Rashi (referencing Vayikra Rabba 2:1) understands the passage to mean that if it's so hard to find a single man wise enough to teach Gemara, then one should be particularly cautious with women:
אדם אחד מאלף מצאתי - בנוהג שבעולם אלף נכנסים למקרא אין יוצאים מהם להצליח שראויים למשנה אלא מאה ואותם מאה שנכנסו למשנה אין יוצאים מהם לגמרא אלא עשרה ואותן עשרה שנכנסין לגמרא אין מצליח מהם אלא אחד להוראה הרי אחד מאלף
ואשה בכל אלה - אפילו באלף לכך אתה צריך להזהר בה
One man in a thousand I found- The way of the world is that out of a thousand who enter to learn Torah, only one hundred successfully come out fit for studying Mishna. And out of those hundred who went to learn Mishna, only ten come out fit for studying Gemara. And out of those ten who went to learn Gemara, only one come is successful to teach. He is one in a thousand.
But a woman among all those- even in a thousand, so you must be careful with her.
However, there are midrashim that don't follow rashi's implication of women's wisdom. Continuing from the midrash that Rashi references, the Meam Loez expounds upon the idea that the verse is discussing Abraham and Sarah:
"One man in a thousand I have found" - that is Abraham. "But a woman among all those I have not found"-that is Sarah. If all the excellent traits of a thousand men were pooled, it would be possible to attain to the stature of Abraham. But the combined good traits of a thousand women would not equal the character traits of Sarah, who was greater in prophesy than Abraham.
The Meam Loez here suggests that women can't reach the wisdom of Sarah, not because they are less capable than men, but because of Sarah's unattainable level of prophesy - a level higher than what men might collectively seek.