Reporting this in case a pattern develops with other users. But it might just be a one-in-a-million set of circumstances. This is occuring during hard core mode.

I installed Old World Blues this weekend and played it to the end without too many problems, except that I noticed the Pipboy was coming up slower then before and the game crashed sometimes when the load screen was transfering the character from one place to another. (autosave worked just fine and I could just pick up from there.)

Now I've reloaded a save from before I installed Old World Blues, where I had a different character in the middle of going through Dead Money. After about two hours of play, I'm seeing the sleep (SLP) flag coming up. That last time I played dead money in hard core (with a diffferent character), the SLP flag never came up. Now it is. And at the same time, the RAD flag come up on the characters too (legitimately) . I got the character to an autodoc and used the adrenilin function. That worked ok for the SLP. But when I click the RADAWAY button (on either the RAD screen or the AIDS screen), crash to disk occurs. That's all the info I have for this. I'll reload my saves to back before the SLP popped up and see it is just a flluke. But I'm wondering if my saves before Old World Blues are not compatible with having Old World Blues installed.

In the immortal words of Emily Littella, "Never mind." Went back to a save before SLP showed up and used an autodoc adrenalin shot to get the SLP level down, and then hit RADAWAY for the Rad level and it worked find. It was fluke problem.