Hi,
It's unclear which version of DSpace you are using, and how you are attempting to run this import (via a user interface or via commandline, etc). So, it's hard to give any more advice. But, the basic error here appears to be saying that your Simple Archive Format isn't "valid".
If you need more help, let us know on this list & please provide us with more information about your DSpace setup and how you are running this import, etc.
Tim