This installer fixes the problem loading the photoshopimport.aip and photoshopexport.aip plugins in In Illustrator CS4 running on OS X Yosemite.
The launch log output in Console should throw these errors:
Adobe Illustrator[521]: Error loading /Applications/Adobe Illustrator CS4/Plug-ins.localized/Photoshop Formats.localized/PhotoshopExport.aip/Contents/MacOS/PhotoshopExport: dlopen(/Applications/Adobe Illustrator CS4/Plug-ins.localized/Photoshop Formats.localized/PhotoshopExport.aip/Contents/MacOS/PhotoshopExport, 262): Symbol not found: _map_fd
Referenced from: /Applications/Adobe Illustrator CS4/Adobe Illustrator.app/Contents/MacOS/../Frameworks/AdobePSL.framework/Versions/A/AdobePSL
Expected in: /usr/lib/libSystem.B.dylib
Adobe Illustrator[521]: Error loading /Applications/Adobe Illustrator CS4/Plug-ins.localized/Photoshop Formats.localized/PhotoshopImport.aip/Contents/MacOS/PhotoshopImport: dlopen(/Applications/Adobe Illustrator CS4/Plug-ins.localized/Photoshop Formats.localized/PhotoshopImport.aip/Contents/MacOS/PhotoshopImport, 262): Symbol not found: _map_fd
Referenced from: /Applications/Adobe Illustrator CS4/Adobe Illustrator.app/Contents/MacOS/../Frameworks/AdobePSL.framework/Versions/A/AdobePSL
Expected in: /usr/lib/libSystem.B.dylib
This fix addresses the issue by injecting libmap_fd into the executable image at runtime.
libmap_fd is developed by Benjamin Fleischer (https://github.com/bfleischer/map_fd) and provides a custom implementation of the map_fd syscall based on POSIX mmap that is compatible with Yosemite.