Upon further testing, several weeks later, the first import of the same data file succeeded and created the parent/child account structure. How ever after deleting and re importing the errors occur.
It's my guess that the system does not immediately delete records and when attempting second import of the data, the deleted records are restored, with a system assigned id, thus the ParentId lookup fails.
If true then this makes it near impossible to do trial data imports. The import is rather fickle and I never get the map and all files clean for a perfect import each time.
So if true, how long do I need to wait for the records to be disposed so I can try another import???
Al
Al