I was a happy user of SpamSieve with my old iBook G3 running 10.4. I just got a new MacBook with 10.5.4, and I used Migration Assistant to transfer all the programs and files to the new MacBook.
Now Mail does not work with SpamSieve. Mail does not automatically load SpamSieve. When I do run SpamSieve before retrieving mail, it causes Mail to crash, and all new mail goes into the In box, and none into the Spam folder.
I tried downloading SpamSieve again and re-installing it, but Mail still crashes.