Originally Posted by
ShneekeyTheLost
Some basic things:
1) Modloader is no longer necessary with the latest edition of Forge which comes with the Forge ModLoader (FML) as part of the package.
2) If you are using an older version which requires ModLoader, make sure it is ABOVE Forge in the TOP mods window (the ones that goes into the .jar)
3) Make sure that your versions of Forge and ModLoader are compatible with the version of the mods you are using
4) Make sure your mods are a) compatible with the above, and b) just need to get dumped into the mods folder
5) If you're getting blockID conflicts, that's not a problem with MagicLauncher. Just go into the config files and change the block ID's to avoid confliction. With the latest edition of Forge, which also incorporates the 4096 fix, it's probably easiest to start off at 400 (vanilla eats up something like 251-388 for some reason, so I just start a 400 since it's the first nice round number after 388 to ensure I avoid problems), take a major mod with a lot of block ID's, and start going down the line with 400, 401... Rinse, wash, repeat with other mods until it runs properly.
6) Make sure the version of MagicLauncher is current.
7) If none of these steps help, try MultiMC, it is somewhat more user friendly, and may be more intuitive for you to use.