The import had problems in that (not sure of my terminology here) the php processes on the server could not access the cgi-bin side. I got the host site administrator involved, and once he figured that out and enabled the cgi access, he ran the import himself.
Looking in the Database Tools on the Control Panel, ubbt_IMPORT_MAP shows: 32298 rows, Data_length=662.36 KB, Index_length=1.08 MB
Here is some data from the table:
SELECT * FROM ubbt_IMPORT_MAP where OLD_TOPIC_ID=5252
SITE_ID POST_ID OLD_TOPIC_ID OLD_POST_ID OLD_FORUM_ID
1 31782 5252 1 1
1 31783 5252 2 1
1 31784 5252 3 1
1 31785 5252 4 1
1 31786 5252 5 1
1 31787 5252 6 1
1 31788 5252 7 1
1 31789 5252 8 1
1 31790 5252 9 1