Well, it looks like Embarcadero has introduced some changes to their ZLib implementation in the latest Delphi update, which broke compatibility with earlier ZLib versions. While this won't be a problem for Windows-only Applications, because all of them would be using the same pre-compiled ZLib files included with the RTC SDK, to ensure cross-platform ZLib support, you will have to tell the RTC SDK to use the default ZLib implementation included with Delphi, regardless of the platform you are targeting.
To do that, you need to open the "rtcDefs.inc" file in the "rtc\lib" folder and remove the dot (.) from this line ...
{.$DEFINE RTC_USEZLIB}
... so it looks like this ...
{$DEFINE RTC_USEZLIB}
.. then rebuild the RTC SDK and rebuild ALL your Projects.
This should make all your Projects use the "ZLib" implementation included with Delphi,
which should be compatible across all the platforms supported by Delphi, solving your ZLib exception.
Also, make sure to BUILD your Projects (not just COMPILE),
because the code being compiled depends on the target platform (it is NOT the same for all platforms).
PS. We have
discontinued support for all platforms other than Windows some time ago and have made a public announcement again about this, here:
https://rtcforum.teppi.net/index.php?topic=1717.msg5792#msg5792