Ok, just figured this last one out.  When Profile carried forward the file,  (there were two files), it populated the 'individual' fields (name, SIN, DOB) so the slips showed up in the individual's names, not in the company name, in the database.  Took out the individuals' information and resaved, and I was able to access the file for transmitting.

Guess we have to wait for next update to file T4s from the 2023 database.  And I'll see if I have success filing any T5s....