Shriveled pbulbs can be the result of over, or under watering - over watering rots the roots, and the plant can't take up water.
I'd recommend using skewers in the media to help determine when to water.
http://www.orchidboard.com/community...hen-water.html
I'd water the ones you have before media is completely dry.
You may want to check on the condition of the roots.
I've also had good results putting a small amount of styrofoam into the center of the root mass or pot - it helps the media to dry more evenly (no sogginess in the center, when the rest of the media is dry).