I downloaded Sybase iAnywhere for MacOS X and I discovered a bug that makes installation fail if you start the process from a folder with a space in the name. The problem is that you don't get any error: the Sybase folder is created but the files are not copied into it.
I moved the install file from my "Download Web" folder to Desktop and all went fine. But I figured it out after half an hour... 
I hope it helps