I have the normal TSF and 1.20 version of JJ2.
I used the plusifier to install JJ2+ on my computer, worked great.

However, I tried to install the JJ2+ patch on my friends computer, but it fails to patch his .exe because he has "Jazz Jackrabbit 2 TSF:JK Avalon" version.

What is this version, and how to fix the problems?

Thanks for clearing this up, i will try this.

lol I was able to install plus on it. It's rather easy, actually. I downloaded TEC and used a hex editor to change it back to 1.24. I then replaced my jazz2.exe and plusified that. It has worked fine ever since.