"Failed to download recording" when trying to archive

[sipiguy]

I queued-up several (a dozen?) TiVo recordings to archive and got them all started in the right directory. Suddenly they all started reporting "Failed to download recording" even though a vid-name.download.ts (mpeg2) file was written in the archive folder. Now any attempt to archive any of these TiVo recordings will report the same error message, even if started from a different computer system. After several attempts to debug this I switched to a new group of TiVo recordings. Three were archived successfully but the fourth one reports the error. Subsequent attempts to archive other TiVo recordings work but once a download fails it apparently cannot be downloaded thereafter. Computer restarts and a TiVo power-off had no benefit. Once jiggered a recording stays jiggered. Any insights to avoid this issue or suggestions to restore downloadability would be greatly appreciated! I am running Win7-64bit home-premium +sp1 or Win7-64bit professional + sp1. The log-file from the Win7-home system is attached. Archivo and Java were downloaded/installed on 9/10/2017.
archivo-log.txt

[sipiguy]

Did some further research using 17 recordings that all report "Failed to download file". Eight recordings appear to download fine ("End of file reached") but bytes_read < bytes_expected. Six recordings report "Invalid TS packet header for packet 52xxxxx". One recording reported "No Transport Stream exists with PID 0x1263" and one reported "Decrypting packet in stream 0x0a41 failed". All of the recording-name.download.ts files are 0:59:58 to 1:00:00 long so they appear to be the correct length. It is interesting that certain numbers recur in the bytes_expected: 1,709,178,880, 2,076,180,480, and 2,202,009,600. I uploaded a spreadsheet that summarizes these findings along with the archive.log for this experiment.
The equipment setup for this was as follows: the TiVo and PC are in the same room, alone on a dedicated gig-Ethernet switch, with one switch port connected upstream for internet access.
I would like to understand why these issues arise so I can try to mitigate/avoid them. Moreover, is there a way to resume processing of the .ts files and complete generation of the .mp4 for each of the "failed" recordings?
DMfolderinfo.txt

archivo-log_darkmatters.txt
DMsummary.xlsx