Forge Mod Loader Problem

[AJ Varchetti]

So recently I was going into mine craft to run up my world, when I got a message that says the following:

 

"Forge Mod Loader detected that the backup level.dat is being used. 

 This may happen due to a bug or corruption, continuing can cause damage your world beyond repair or lose data / progress. 

It is recommended to create a world backup before continuing"

 

So I clicked the yes button on the bottom of the pop up and my world started loading again, but then the same message as before popped up.

 

Does anyone know how to fix this so I can get on my world? Thanks in advanced!

(If anyone is wondering the mod pack it is Journey to the Core version 1.9.2)