I upgraded today Zenphoto (1.6.3) to 1.6.4 on my localhost computer.
It does work, but I will test it a bit more before upgrading my online Website.

Thank you to all developers.

My "Hello World" macro does work now, as mentioned by acrylian in an older message.
I will be able to study macros.

Also, no more printContactForm errors in logs.

Thank you again.

Online site is updated to 1.6.4.
Successfully tested.
Happy, I have re-used your "Donate" page.

Thank you!