The exposure information looks to be what I would expect - meaning it is OK.
Any time the flash is used, the shutter is set to 1/30th second on this camera.
The other settings are within bounds.
The ZD15 flash is only rated to 15 feet (10 feet if using red-eye setting).
If something is directly in front of the camera (such as a person) the flash uses that object as the exposure setting and the object will be properly exposed and anything behind that object will be underexposed (dark). That is normal.
If nothing is nearby (in front of the lens), the room should be well lit (if it is a small room).
If your flash pictures are different from that, post the picture for us to see.
If you have your picture somewhere on the internet, just post a link to the photo.
If you don't have the picture on the Internet you can open a free account with www.photobucket.com and put your picture(s) there. When you look at the photo there will be some links near the photo. Use the link called "Direct Link". Put that link in the message you post here and then we can see the photo.