Your KMZ file is not correct. If you zip up the t-11 directory, it works:
It currently looks like this:
[lross@JJ kmz]$ unzip -l t-11-1.kmz
Archive: t-11-1.kmz
Length Date Time Name
-------- ---- ---- ----
0 07-07-13 12:06 t-11/
3655 07-07-13 12:43 t-11/t-11-bana.kml
0 07-07-13 12:08 t-11/files/
1039 07-04-13 21:21 t-11/files/subway-blue.png
If you create it from the t-11 directory so it looks like this, it works:
[lross@JJ t-11]$ unzip -l t-11-1a.kmz
Archive: t-11-1a.kmz
Length Date Time Name
-------- ---- ---- ----
0 07-07-13 12:08 files/
3655 07-07-13 12:43 t-11-bana.kml
1039 07-04-13 21:21 files/subway-blue.png