I am either no expert and have this plant in my third year with aparantly no problem.
But in your case you should have a close look at this page where I posted my assumptions about this problem crown rot is mostly caused by boron deficiancy
http://icps.proboards.com/thread/7261/b ... s-crownrot
This deficiency might be the cause for many cultural problems with this and many other carnivorous plants (others too).
This element leaches out very quickly and can’t be retrieved by the plant from its older leafs.
Maybe even not form its prey because it’s mostly in the cell membrane.
We like to clean our plants and total decay would be the only way to bring it back into the plant.