Hi there!

Your Project

That error you got on your game: "Cannot read property 'getHexOrName' of undefined" it's because one of those things:

1. missing EliMZ_Book
2. EliMZ_Book is outdated
3. EliMZ_Book is not above the EliMZ_Timer
4. Some plugin parameter on EliMZ_Book is bad configurated triggering a silent error and failing to load the EliMZ_Book, resulting in Eli.ColorManager being undefined.

Try to check those things and see if the problem is solved.

My Sample Project

That is a little trick. Because I never managed to replicate the str.replaceAll issue. It seems that I also forgot to answer the OP Team Dream Treasure to try to check on this =/ The screenshot he sent me was not the one I asked, so even now I don't have what I need to investigate that.

Now, I just did the following:

Attempt 1

• Downloaded the Sample Project from the itch io page.
• On the first map I just hit playtest, it runs normally no error.

Attempt 2

• I disabled all the plugins, and just turned ON EliMZ_Book and EliMZ_Timer. Worked just fine, no errors.

Attempt 3

• I updated the EliMZ_Book and EliMZ_Timer, downloading that plugins from their itch io page, and put them on the js folder of the sample project. 
• Open both their plugin parameters to make sure they also updated and nothing is wrong there
• Hit playtest, no errors at all.

Continuing...

Now, the error showing on your screenshot is "Cannot read property 'clamp' of undefined, on the line 3724 of the rmmz_core.js file.  Which is this line on the core versions 1.9.0 that the sample project have:

Now, some backSprite is trying to set it's alpha value. And that value is undefined. Following the stack trace, it seems that the Window_TitleCommand is what is trying to set the backOpacity value and that value is undefined. i really don't know why this is happening.

I'm not managing to trigger the error again, so i don't know what is wrong. The Sample Project is a little outdated... Maybe you can try to update the RPG Maker Core files and EliMZ_Book and EliMZ_Timer to the latest versions.

But you need to tell me exactly your steps. Because that updated error screen is from the last updated version of EliMZ_Book, but the sample project does not have that EliMZ_Book version by default. So you just copy and pasted an updated version there? What exactly was your steps?