the same problem (SHA1 hash mismatch) on my nas (wd mybook):
create backup from nas -> restore in nas -> mismatch
create backup from ubuntu (10.10) -> restore on nas -> OK
create backup from nas -> restore on ubuntu (10.10) -> mismatch
means: the upload to my ftpserver failed, not the restore!
the same problem (SHA1 hash mismatch) on my nas (wd mybook):
create backup from nas -> restore in nas -> mismatch
create backup from ubuntu (10.10) -> restore on nas -> OK
create backup from nas -> restore on ubuntu (10.10) -> mismatch
means: the upload to my ftpserver failed, not the restore!