I see no ZLIB1.DLL, version 1.2.7 for ZLIB despite the fact that the
main web page claims there is a link to the officual version.
The last version of ZLIB1.DLL available was version 1.2.5 but this
produced errors on linking with Microsoft LINK which complained of
multiple .TEXT segments with different attributes. I dont know if this
was ever fixed.
The last version of ZLIB1.DLL that I can confirm works is 1.2.3.