I recently started working   on a new dimension with forge  for my mod. I registered my dimension and my WorldProvider with DimensionManager and I wonder how i can get to this dimension now. I tried this: 
  
//////////////////////////////////////////////// 
   public void onEntityCollidedWithBlock(World par1World, int par2, int par3, int par4, Entity par5Entity) 
    { 
    	EntityPlayerMP entityplayer=(EntityPlayerMP)par5Entity; 
    	MinecraftServer.getServer().getConfigurationManager().transferPlayerToDimension(entityplayer, 11); //  11=id of my dimension 
    
    } 
/////////////////////////////////////// 
But  you obviously cant  cast EntityClientPlayerMP to EntityPlayerMP , and I cant figure out how I can get the player to the dimension on a differrent way   . (Note: my mod isnt smp yet). It would be great if someone can tell me how I can solve  the problem , because Im not a very good coder and (as said before)I dont now any other way to get to my dimension.( I am using forge 4.2.5.303) 
  
Thank you in advance   
  
  
PS: 
Do I really have to unregister the Dimensions 0,-1 and 1 to get the DimensionManager to work? 
  
  
I solved it by doing this: 
  
  public void onEntityCollidedWithBlock(World par1World, int par2, int par3, int par4, Entity par5Entity) 
    { 
    	if (par5Entity instanceof EntityPlayerMP) { 
    		EntityPlayerMP playerMP = (EntityPlayerMP)par5Entity; 
    		playerMP.mcServer.getConfigurationManager().transferPlayerToDimension(playerMP, 11); 
    		} 
    
    }