[1.7.10] Does adding commands to a Mod requires a new World?

[American2050]

So I followed this Tutorial on how to add commands on my mod. http://www.minecraftforge.net/wiki/Server_Command

 

However when I replace my old mod in my testing environment and try to open an already generated world, it just hangs out on the Loading world.

 

I can create new worlds, and when trying on Eclipse it works ok.

 

Is this an expected behavior or I'm missing something?

[delpi]

Look at the server screen.  It is probably waiting for your to type in '/flm confirm'.  You probably changed block or item references between mod versions or such.

[American2050]

Look at the server screen.  It is probably waiting for your to type in '/flm confirm'.  You probably changed block or item references between mod versions or such.

I think I did it wrong from the beginning

 

I really don't need a Server Command, but just a command to show player some info