zip asdf backup.1 gives "zip warning: name not matched: backup.1" ?

[Michael Kahle <michael.kahle@scc-wi.com>]

I am trying to zip a file for a vendor.  The file is named "backup.1" and is
4.7G in size.

When I run the command:
zip asdf backup.1

I get the message:
      zip warning: name not matched: backup.1

zip error: Nothing to do! (asdf.zip)

Now this is a large binary file and I know there are better ways to compress
this file, but the vendor requires it in PKZIP format.

Any clues as to why this isn't working?  The '.' character is not a special
one in bash so I shouldn't have to worry about enclosing it in quotes, but
just in case my understanding is incomplete I have tried these other
combinations as well with the same error resulting:

zip asdf "backup.1" &
zip asdf 'backup.1'

Is there some sort of size limit I am up against here?  I am using Zip 2.3
that is packaged in sid.

Thanks,

Michael