Most of this was explained here:
http://www.bit-blot.com/forum/index.php?topic=4251.0 (same board, so look out before risking a moderator rant

)
About shooting the pearl, just keep a shot charged until he is between the barrier, and release it when he is in between? Or didn't you mean that?
Maybe its just the touchscreen fumbling, though.
EDIT: I forgot, doesn't the iPad version allow targeting enemies/things by tapping on them while in energy form? Target the pearl if you didn't already, that makes it easier.