When you see the blank square boxes, it means something in the content failed to translate to the device.
When you see the box with the red X, it means a picture failed to load.
In the cases above, they are the "smilies". I think there's a different set between the mobile interface and the computer interface, and there's nothing in the software to alter the set for the device you're using. If you are reading with the same type of device that was used to create the content, you see the smilies. If not, you see the box.
Pictures failing to load can be caused by many different things (picture not in correct directory, consumption device has no software to use to interpret the object, it's too big and timed out fetching it, etc.)
Apple devices don't have Flash. (Not you, the Adobe software). Therefore, anything on the Internet with Flash content can't be displayed on an Apple device.
If you don't want to upset customers with your communications, just use text, and not the cutesy things that are specific to each type of device (in this case the smilies).
Jim