Since the 1.4.5.1 version I can't upgrade my zenphoto. Today I tried to upgrade to 1.4.5.4 and the installation failed completely. My whole Zenphoto was gone and I only got a blank page with php text
I re-installed 1.4.5, because it's the only one I manage to get to work

We will really need more infos like error log entries to be able to help. Just to note, I upgraded several sites on several hosts today and had no problem at all.

I deleted Zenphoto from my webserver and re-installed the version 1.4.5.4 After this installation I saw in the folder Themes that the themes for example kish-my-father now have the extension .txt and not .css anymore. How can I change the outlook of the theme if there isn't css anymore?
I think this was the reason I had problems with updating since 1.4.5

So you have made custom color schemes for EF+?

What you will find is that the color schemes are now controlled by definitions set by the text files. This was done to make maintenance much simpler for the themes. There is now only one CSS description and the color schemes set the appropriate definitions and perhaps the translation array.

Alternatively you can simply make a copy of the theme and change it to use your custom CSS file. Of course, then you have the same maintenance issues that we made this change to address.

Yes, I made a custom color scheme in EF+ style Kish-my father. In meanwhile I found in the folder themes that every theme has a base.css with codes that are applied in the style .txt files.
I'm going to copy the EF+ and customize the colors in the .txt file of the style I want to use, so the colors will be defined in the base.css