I've had crashes in the 64-bit client since it was introduced on area transitions or when switching characters. But the 32-bit client always worked fine. Now since a few updates (I'm guessing since 59.4) it also happens in the 32-bit client.
Update: DDO now works for me again without crashes (thanks Onyxia2016 for the tip)
I tried in order:
1) tried both 64-bit client and 32-bit client (neither worked)
2) Repair from game launcher options (did not fix it)
3) Setting graphics card in launcher options (did not fix it)
4) Disabling sound inside game audio options (did not fix it)
5 Ran DXdiag, no problems reported.
6) Uninstalled entire ddo client, reinstalled ddo client, inside game options I set DirectX version to DX9, restarted game client (now the game worked without crashes!!!)
7) Changed game options DirectX version back to DX11 (It still works without crashses).
So in short, if you have this problem, try logging into the game and select Options->Graphics->Graphics Hardware Level->DirectX9 to see if that works for you. If that doesn't work, try reinstalling ddo.
As for what the cause of the problem was, I'm not really sure, but I highly suspect it's somehow broken or missing dll files in the ddo install folder, caused by simply using the DDO Launcher (it would not be the first time DDO launcher has completely screwed up my DDO installation). I highly doubt that the windows folder DirectX files were broken. DX10 and later all come with the DX9 files included and the windows files shouldn't really be the problem unless you have a corrupted hard drive, right? I kind of wish the repair option in the launcher fixed this issue though, what's the point of having a repair function if it can't be relied upon when it comes to fixing missing or out-of-date files in the install folder?