How download it? Always appears 404 in a page with nothing. This happen with me in 3 or 4 different mods. :(

Why i cant installlll????? :((((( Always appears 404. Or annother page but i still cant install it

I cant install. When i click in link appears 404

When I'm playing MM8BDM, I sometimes encounter the "challenger approaching" situation. I have no idea why this happens or what I gain by winning these battles. Another thing I need help with is that sometimes "Boss Item Morph..." and something else (I forgot the name) appears in the "Classes V" mod. I don't understand that either. If anyone can help me, I would greatly appreciate it.