(I had a user with this problem before, and once we completely erased and rebuilt their hard drive, it went away. This is not a viable solution, so I thought I'd toss it out here.)
I have a user with Notes 6.0 client on Windows XP. Often (not always) after sending a message with a file attachment, NSD runs and locks up the Notes client. Nothing can be done in Notes until they shut down completely. This usually happens only once each day.
At the time of the crash, it appears that NLNOTES.EXE has started ntaskldr.exe. I have several nearly identical log files from NSD, but am uncertain how to interpret them.
The last time this happenned, we tried rebuilding the Notes User ID, re-installing the Notes client, and rebuilding the Windows XP profile. We finally wiped the hard disk and rebuilt the machine. This was not a big problem before, as the problem occurred within the first few weeks in use. The current machine has been in use for about a year, and I really don't want to have to rebuild the software from scratch.
Any suggestions? I can forward a log or two if you wish...