Hello,
If the filesystem, or transfer programs, for whatever reason, are not liking the oversized files, then a simple solution is to create a smaller file.
First determine what is causing the file to be so large.. eg:
databases
email
html/php/images data (under public_html)
Login as that User, then go to:
User Level -> Create/Restore Backups
Uncheck the one option that is making the backup very large, then create the Backup at the User Level as the User. Note you may need to temporarily give the User unlimited disk space if the file is going to put him over his limit.
This will create a backup in /home/username/backups, which you can then transfer over and restore normally. You can rename the User backup file to be the naming format that the Admin Level -> Admin Backup/Transfers uses, as the contents of the tar.gz files are the exactly the same.. less whatever you've not included.
Restore the file normally.
Then transfer the rest of the data manually, in chunks, etc.. as needed.
Or use the same process as above, but use the inverse options with the checkboxes.
John