No mod loader, it said that Forge would work for that or something. I don't usually deal with these just ID errors (back before you could download a mod to do that for you...) and I haven't played sense 1.7.3ish so a little push in the right direction would help.
if you could go into your .minecraft there should be a folder called crash-reports then in there a .txt file if you could open up the newest one and copy that to here.
http://www.minecraftforum.net/topic/1495041-145-modloader-biomes-o-plenty-adds-57-unique-biomes-source/
http://www.minecraftforum.net/topic/211517-144145forge-balkons-weaponmod-v110-long-weapons-extended-reach/#install
Newest modloader and forge (I did universal instead of source, is that the problem?)