Packet libz1 missing

[Gerhard Heid]

Hallo,
i need xserver-vga 3.3.5-2 for Nvidia Riva TNT2 graphic   i386 -unstable,
but dpkg needs libz1-Packet to be installed before. This Packet is not
listet at all.
How to solve this ?

Best  Regards

Gerhard