Unreliable Logon for Synchronize

The SBF logon for synchronization is unreliable. It works reliably for Simulate, Run in the SBF program, and with the Hot Key. But when scheduled to run when logged off the computer, it fails more often than not. I have a group with 3 profiles, for individual folders. For testing, I would set the Scheduler to 5 minutes in the future, and logoff the computer. Right now I am looking at the 3 Log files of the latest run. 1 Success and 2 Network Failures. This time both failures are because of an Invalid Username. Sometimes it is because of a bad Password. Sometimes both. I read your comment about the flaky MS network issues, so I tried to test thoroughly with numerous settings. I think I have a smoking gun right now.

Here are some possibly pertinent details:
SBF v. 6.4.3.0
LapTop running Win 7 Home Premium 64
DeskTop with Win 7 Pro 64 (both SP1)
Home network on modem/router. Laptop via wireless.
Folders for synchronizing listed in Homegroup on both, in the same accounts.
Logon & PW for computer same on both for accounts used for SBF profiles.
I tried giving it up to 30 seconds pause in the Misc. settings.
I tried including, or not, the logon parameters for the DeskTop in the Network setting.
Folders are on the same logical drive letter on both, and have same names.
This SBF running on LapTop. (It cannot be awakened from network.)

Is there anything else I can try?