I can't edit tilesets on a map in JNGP

[daverave1212]

Whenever I try to modify tileset from the Extensions tab, i get an error saying 'Too few cliff tiles have been selected'
I'm trying to work with a realtexture imports map (Born2Modificate)
I guess it has something to do with the cliffs (there are 4 cliff types...)
I did not remove any tileset, i just tried to add some and i still get that error
I searched on google but i couldn't solve the problem
Help?

 

[daverave1212]

fixed
i just had to reset the tileset and the tileset from the extensions too