Personal Ancestry Writer II (PAWriter II) version 51, 27 April 2006 is out and address an obscure bug that cropped up from the last release.
It can be downloaded here
An obscure problem was uncovered with the automatically generated .bkp data file. In certain circumstances, there may be a conflict in file name extensions (the part of the file name after a period) in OS X which doesn’t occur in OS 9. This seems to have shown up when backing up to iDisk. Just in case, version 51 now generates a -bkp file (in both the OS 9 and OS X versions) — using a dash rather than a period — so there can be no file name extension conflict.
The new -bkp file will be generated the next time you save changes to your data file. Then you can trash any old .bkp file.