Got reply from Steinberg:
Panagiotis Kontos wrote: Unfortunately we discontinued technical support for the product you are requesting support for.
Please note that there will be no more updates, bug fixes or patches. We also cannot provide replacements for installation discs or manuals.
Officially Cubase Essential 5 was never compatible with Mac OS X 10.9.
Thanks for your understanding! If you are experiencing further problems, please do not hesitate to contact us again.
Steinberg Technical Support Representative
My install solution (only if you have Cubase AI/LE 5 CD):
1. Install Cubase AI/LE 5 from CD
2. Go to "Applications" and rename "Cubase AI/LE 5" to "Cubase Essential 5"
3. Now click "show package contents" and go to "MacOS" folder
4. Rename binary file "Cubase AI/LE 5" to "Cubase Essential 5"
5. Downolad and install "Cubase 5 Essential 5.1.1 Update"
Prologue and some VST plugs will be missed.