Collisions simply aren't working

Hi,
I'm running into all sorts of problems in making my game. For one thing the collisions aren't working.

When obj A collides with obj B, obj A should play another animation. Yet obj A can even overlap obj B without this event taking place. I've tried just using fine detection so the sprites would detect one another, and I've tried using active pictures- colors squares that follow each entity.

As I'm sure it could be due to many reasons, I'd just like to know- would the fact that the game is running slow cause this to happen? Perhaps it skips the frame in which the two objects would have collided?

EDIT: I forgot to mention- sometimes the collision works, other times it does not. And it seems that if I move object A into object B, the collision works, but if object B reaches object A on its own, it doesn't. (I have a scenario where I control object A and obj B follows it).

I've also tried switching between "collides with" and "overlaps with".. would anyone be willing to explain the difference to me?
Thanks very much

Are you sure the collision itself isnt working, or is the animation not working? If you are trying to play a special animation, and you already have an animation like "Walking" playing, the animation probably wont play because it will be overridden by "Walking" immediately.

Sorry, I'm really not sure what you mean. But all of these animations are custom animations with custom names

active pictures have had collision problems recently (so they probably won't help), which should be fixed by the next beta

try setting the Stopped animation for Object A to Loop. It probably won't help here, but it helps with other things regarding animations

Difference between the two:
Collides With - Triggers the actions only once when the objects touch, and won't trigger again until they stop touching and touch again
Overlapping - The actions are triggered continuously as long as the objects are touching

Mussashimits, why not put a simple example of what you're doing in the File Archive for us to take a look at and fix for you. Just use very simple small animations, because there's a size limit of about 300kb.