iTunes is using the feed at http://www.theappreviewzone.com/feed/ - presumably the result of the 301 redirect Feedburner has apparently set up for you.
This feed contains one episode which contains playable media and several which don't.
On subscribing in iTunes only the one episode appears, because iTunes does not display episodes with no playable media; the Store is the same.
Of course, if you look at the feed in any other RSS reader it will show all the episodes. Your page at
http://www.theappreviewzone.com/
shows the same episodes, and the feed is derived from this. All this is is behaving as you would expect. I don't know whether it's possible to set WordPress to produce a separate feed which includes only the episodes with media. If it is, and you can get such a feed working, then you will have to go through the process I described in the page Iinked to above. If you can't edit the feed in this way you can try emailing them at podcasts 'at' apple.com and asking them to change it for you. You will need to give the the Store page URL, the URL of the new feed, and presumably the URL of the now non-existent Feedburner feede (or both that and the present feed).
As you see there is actually no problem in iTunes at the moment in having a mixture of episode types because it ignores the non-podcast episodes. However, WordPress is probably by default limiting the number of episodes in the feed to around 30, removing older posts once that limit is reached. This will result in your earlier podcast episodes disappearing even though there are only a small number of them, so you will need to increase the number of posts allowed in the feed - there is presumably a setting for this.