There have been some recent talk about the nightly heal and can on occasion (usually when a node is misbehaving) hang the network and in some cases knocking the network completely offline. Here is one thread where Chris comments on the nightly heal
Also please check the thread Bruce linked to for info about the remove node in habmin and using zensys tool. Mark and Chris have been working on getting habmin to function better at getting rid of died/ghost nodes
Robert @rrgeorge
if you consider your issue fixed please mark the thread title as [SOLVED] and put a check mark in the thread that helped you fix the issue
thanks