Painfull

Ahh okay, seeing this line : [04:03:58] [sEVERE] at InvTweaksObfuscation.getPlayerContainer(InvTweaksObfuscation.java:78) I think it is Inventory tweaks responding to it. It is already submitted at the mod makers github. https://github.com/mkalam-alami/inventory-tweaks/issues/234 It will be fixed in the next milestone probably around 1.3

Does the server start further or is that the only thing in the logs?

Well easy fix there. Do not use your middle mouse buttons in the menu. Just do not say anything whilst your starting minecraft. Have you tried it with vanilla Minecraft? If it bugs out there it is a vanilla bug.

I think it's something to do with your NEI. But what excatly I do not know. Did you change anything to NEI?

/reload breaks alot of stuff in a Tekkit server. Save-all then stop server then restart it. Should fix your problems.

ID's on server do not match client ID's

You might have a space in a place where it's not expected. Thats what I had with a server of mine.

Yep known bug, is just visual as far as I know.

Cobble gens with block breakers cause a lot of lag. Try using stuff like EE Energy Collectors and Anti-matter Relays, Much faster less lag.

Try replacing the chest. Try the quarry input into an other chest, on a other place.

Can you remember where you logged out? Then your friend can look around. Also ask if the server is 3.0.4 because that's the server version that has a big bug crushed.

Some people say Reload a few times. I say try to get Optifine out of the modpack.

Can you post the error log up until the error starts? Sometimes it gives us more info about your error.

[13:19:52] [sEVERE] Adding mods from C:\Users\Harry\AppData\Roaming\.minecraft\mods\MoCreatures.zip [13:19:52] [sEVERE] Zip found. [13:19:52] [sEVERE] Failed to load mod from "mod_mocreatures.class This seems to happen a few times. It looks like Mo'Creatures is failing to start. Which is as far as I know NOT in the recommended Tekkit build.

Also removing Optifine is also a solution.

Can you post the whole error log? Also the Error you're getting on screen in your minecraft window says you don't have the same mods installed as the server. Try reinstalling Tekkit.

You're Java 7 is likely not being used on the server. As this already had issues with an older version of tekkit http://forums.technicpack.net/threads/mod_ic2advancedmachines-unsupported-major-minor-version-51-0.2324/

Did you try to reinstall Tekkit? The error just means that the server requires mods you don't have installed, so reinstalling Tekkit should do it. If that fails post and I'll try to help more.

Ok, we need more info for this one. 1: Is it an open server or a personal server? 2: Are you sure there is no pipes that's pulling anything out?

It can be that he placed an item, which the server gave an different ID than that you have. So when the server wants to give you the ID for the block you don't have the right ID and you get the error. Ask your friend what he placed and which ID he has for it.

Sometimes, the java version in each Operation System (Windows,Mac,Linux) have just that slight difference that kill the force ID changes. So yeah you have too figure each error as it pops up until you have no error's left. Welcome to server hosting.

Let them try: 24.6.117.155:25565 if that doesn't work check that the port is correctly forwarded

You have the picture because you lack basic Google-ing skills.

Did you start Tekkit before trying to do this. It creates the file after first setup.

It is done, you can connect. It says "20:49:16 [iNFO] Done (9.074s)! For help, type "help" or "?" 20:49:16 [iNFO] [Railcraft] Loaded 0 saved Anchors 20:49:19 [iNFO] Creating Railcraft Save File" See it says done, connect and have fun.