iPhoto needs some old 32-bit system frameworks, that are no longer supported on any system version since macOS 10.15 Catalina. The last system version to support iPhoto has been macOS 10.14 Mojave.
Now is your last chance to create Photos Libraries from your iPhoto Libraries and save the albums and other work you have done in iPhoto. Once you move on and upgrade to macOS 13 Ventura, you will even no longer be able to open the iPhoto Libraries in Photos and to create Photos Libraries from them. Then all you will be able to do is to import the photos and videos from iPhoto Libraries, but the albums and keywords and other metadata will be lost.