I have an exterior wasteland area I have modified. There were several trees that I needed to relocate, so I moved them underground----I know you're not supposed to delete them or it causes big problems-----but their "ghosts" are still in the original location. So, I went and checked them as initially disabled, but this causes my game to crash on load ( I am assuming it's because I should have initially disabled them instead of moving them, and not both). Now I'm stuck and can't figure how to get rid of the "ghosts". Can anyone point me in the right direction?
Thanks.

You'll need to load up your mod in FO3Edit and delete all the records from your mod that overwrite the vanilla trees. This will restore your trees to their original locations. Then you will want to move them again in the Geck and then generate a new LOD. The 'ghosts' as you call them are the LOD trees - the visual representation of the trees at longer distances. LOD data will remain even if you move the trees. I am guessing that by disabling them, the LOD Data has some null pointers (pointing to trees that aren't there) and this is causing the CTDs. I can't give you a how to on generating LOD data, I just know it takes a very long time.

I thought you could just generate the LOD data for one wilderness cell at a time if you wanted.
But, you would have to include that new LOD file with your mod if you plan on distributing it.

I've never done it myself, but I have read that even for a single exterior cell it can take an hour or two depending on the system. But I have no first hand knowledge of this.

I'll give the FO3Edit thing a shot and see what happens. I know zilch about generating LOD data, so I will have to do some reading if I can't get it to work. Thanks for the help!

Generating LOD can be painfully frustrating and time consuming. Here is a link that helped me get the hang of it. http://www.gamesas.com/index.php?/topic/1050826-lod-data/page__hl__lod After Getting the hang of it I added a lot of new worldspaces to use in my glass window type cells. If you run into any snags feel free to ask I'll try to help.