I have heard others that have problems with updates. Mine has been really good at them. You have to make sure your battery is fully charged and preferably pluged in when updateing. It also depends on how fast your internet connection is. I did my ICS update with my Verizon Air Card. You may have to try to do the update a few times for what ever reason they don't always take on the first try.
This tablet is the best one out there and well worth buying and maintining. The update you are tryi ng for if I'm not mistaken is the one that comes before the ICS update. The final update from Acer for this tab is ICS. There will be no updates after ICS. If you scan the forum here and look for posts from Mrhelper you will find he is the most knowledgable on the subject. Find his posts and you will have answers to just about any question you may have concerning this tablet.