I have the same problem, i played on the server on day and it worked, i came on the next and it says the same thing. I didn't update tekkit, it I go down a version it says I don't even have the mods and even more because its outdated. The owner didn't update the server and I am using recommend build. Can you please help me when i look on the mods page, the mods that it says didn't get loaded like the original theard post say "0 Child Mods" on it. That has to be the problem because only the ones that didn't work said that in it. Please help me i have look everywhere and everyone says "o it just not the right version". I know what i am doing when it comes to tekkit and this is new. Please help me