There are jelly like barriers throughout the game. Five different colours. Blue, Red, Green, White and Black. As you go through the story, Shu and friends will pick up devices that can disable these barriers.
You can unlock the following barrier devices at the following places...
Blue - After visiting the robot town of Baroy.
Red - Defeating the damaged Defense Mecha robot - Ancient Factory.
Green - Pachess town after disabling the green barrier around the town.
White - Defeating the Iron Giant in Noluta.
Black - Sea Cube after boss fight with Azure Abyssal Dragon.
Check out this thread HERE for a list of where the barriers are. It comes from a Japanese gaming site, thanks to Jinx for posting.
NOTE - Not sure which barrier you are missing? Speak to the Fortune Teller in the Lal Mountains Sheep Tribe Camp for her to narrow it down to colours you are missing. Great help!