Your game type (Server or Client): Client
Your Galacticraft Version: Alpha 0.1.27
Minecraft Version: 1.5.1
Minecraft Forge Version: 7.7
Error Report (if applicable):
The game mode the bug occured in: (SSP/Survival Single Player, SMP/Survival Multi Player, CSP/Creative Single Player or CMP/Creative Multi Player): CSP
It didn't give me a error report, only a screen with the dirt background saying the two files share the same name. You should make a bug form, so you don't have to tell everyone follow the bug template.
Just found out it does the same thing with Fluid Mechanics.