Anttl462

I realize this is probably a dead topic, but I've been having the same issue.

Hello everyone! I created an account just to ask this question, so please bear with me if i post this in the wrong place, but do any of you know how to add in galacticraft extensions, such as 4SPACE or the underrated More Planets? I've tried to before by putting the file into the mods folder under .tekkit, but every time i try it gives me an error conflicting with the Galacticraft Mars mod. Perhaps conflicting dimension ID's? I really don't know, but I would love to be able to go to more planets, or depending on the extension, a new solar system!