Dex, AoOs, Uncanny Dodge, and Combat Reflex do not make complete sense. You either house rule or ignore inconsistancies. Yes, this does belong in the rules forum. Yes, you should state what rules are offical and what are your changes to the offical rules to make more sense, ala haste/harm/ect. Hyp has stated the offical rule mechanics.
Here is how I deal with it: You must have your dexterity bonus in general to take an AoO. To AoO an invisble person, you must be aware of an oppent, know the location of said opponent, and know the opponent has provoked an AoO.
Under this rule, you can bluff a person and run past them. You cannot AoO an invisible person, unless you get a good listen check. You cannot AoO while you are climbing or running. You can not AoO if blinded. All this is not what would happen under a strict reading of rules. You can still AoO a person who is blinking, since you have your dexterity bonus in general, as with strict rules reading.
Combat reflexes allow you to take AoOs in some specific circumstances, where you can move but on bad footing (flat footed, climbing, running). Uncanny dodge doesn't allow you to make AoOs, as it does not allow you to keep your Dex bonus (under my rules) but actually gives you a dodge bonus equal to dex bonus in situations where you can move but are otherwise on bad footing (flat footed, climbing, running, invisible opponent).
3.5 will simplify AoOs offically, as they need it desperately. My system is simple, but that doesn't mean it is now or will ever be offical.