From the Battlegear thread, these are common issues of Battlegear and Aether mods:
Block Id conflict
Aether GUI does not work
Sky turns brown
Aether accessories are not visible
Battlegear GUI doesn't display
To fix block id config, here is what you need to do:
Go to the config file, location is [username/AppData/Roaming/.minecraft/config/MineAndBlade.cfg],
open file with notepad and change the number next to the "BannerID" variable to something else, between about 200 & 250, until you no longer get a crash.
2
Go to the config file, location is [username/AppData/Roaming/.minecraft/config/MineAndBlade.cfg],
open file with notepad and change the number next to the "BannerID" variable to something else, between about 200 & 250, until you no longer get a crash.