How to add Custom Field-Effects for Rejuvenation

[DeathTheClover]

Hey all, posting here because I was stumped trying to figure out how to correctly implement a field effect into rejuvenation and was hoping someone would lend a hand? So I want to mention that I know there is a Modding Guide already made for adding custom Pokemon, abilities, moves, etc. However, that guide doesn't really focus on adding field-effects. I understand that it can be complicated, so I tried going about it on my own to see if I could learn but I got stuck after I got an error in game.

 

For context, I started experimenting by trying to add a field effect from Pokemon Desolation into Rejuvenation. The "Darkness Field 3" effect from Desolation that's caused by the Dark Surge ability from Mega Mightyena. Following the modding guide I was able to add the ability itself no problem. I also managed to add in the field effect code itself from Desolation into the fieldtxt.rb file for Rejuvenation. However, the game spawns an error log once I send a Pokemon out with the new ability. Noticing I missed a step, I went and grabbed the .png files from Desolation's "Battlebacks" folder for the backgrounds and named them according to the name scheme used in Rejuvenation's "Battlebacks" folder. I figured this was the issue, but even after doing that I still received another error log. Here's where I got stumped as I don't know exactly what else I have to change to have it work perfectly as it does in Desolation using the correct .png files from the Battlebacks folder. I'll include an image of the error log I keep getting and hopefully someone within the community can help me fix it. Thanks in advance!