The Camping Mod Version: 2.1c
Forge Version: 10.13.2.1236
Minecraft Version: 1.7.10
RailCraft Version: 9.4.0.0
Tested on Multiplayer

Steps to reproduce issue:

• Place a tent in the world

Result:

• Client crash
• [Client thread/ERROR]: SimpleChannelHandlerWrapper exception
  java.lang.ClassCastException: mods.railcraft.common.blocks.hidden.TileHidden cannot be cast to com.rikmuld.camping.common.objs.tile.TileEntityMain

Crash Log: http://pastebin.com/LLd8QxAd

After logging in again tent is placed in the world and can be used.

Fixed tent placing

Thank you for reporting the issue, it seems to be caused by the same thing as issue #11, it will be fixed in the next update.