Unable to Backup FROM a Network Share with TI Home 2009

I moved about 40GB of images off my laptop to a Samba file server. I gave my Vista administrative account access to the files and also used the Set Credentials button to provide my non-admin username/password. I then selected the Network share and initiated the backup.

The backup appeared to start but then failed with the message

Failed to backup file or folder".

Retry did nothing, so I ignored the error. I got two more errors, for '\\' and the folder 'Photos' which is the share name on the Samba file server. Ignoring the error appeared to get me past this point. I saw intermittent activity on the external drive and about 180KB/sec data transfer on port 445 of the file server.

After about 45 minutes TI claimed that the backup operation was successful. However, the backup file is only 281K. The backup contains the folder structure but individual files in the backup look like empty folders.

Is there some magic incantation required so that TI Home will backup FROM a network share?
thanks, Norbert