Installing SAP Sybase client on Windows server 2012 R2

Try checking installer file again. I would recommend that you download it from SAP Market Place. Navigate to below path for getting installer file:

https://support.sap.com/swdc → Installation and Upgrades → A-Z list → search for SAP ADAPTIVE SERVER ENTERPRISE → SYBASE ASE 15.7 → Installation → Microsoft Windows → 51044415.zip

Also note that you need to have following before you proceed with installation:

Microsoft Visual C++ 2010 Redistributable Package (x64)

Microsoft Visual C++ 2005 Redistributable Package (x86)

Microsoft Visual C++ 2005 Redistributable Package (x64)

Check out this SAP thread:

SAP thread