Hi @kitzmiller and welcome to the GreenSock forums!   It seems to me that you're not properly compiling and bundling your files. In order to compile and bundle NPM modules and your custom JS Module files (where you import GSAP and other packages, export your own constants, variables, methods, objects, etc. to make them accessible in other modules) you need to run a bundler like Webpack, Vite or Parcel, just to name a few. It seems to me that the error stems from that.   If yo