Looks like two different problems:
Shiffdaddy, your problem is too dry with too little ambient humidity along with a high temperature. Problem shows from the leaf tip down. Increase your watering and although the leaves will not repair themselves, the problem should stop and the new growth and the plant should be fine.
James, your problem is too much water and appears to be starting at the base of the plant and working upwards. I do not give the plant much hope for survival at this point unless you can salvage a bulb free of rot and start it all over.
CL