Had this issue and fixed it that way:- Go to Curse Config (bottom left)
- Search for Minecraft config (creeper face) in the left
- Scroll down until you find "Launch Method"- Change "Native Launcher" to "Jar Launcher"
- Select the correct version of Java in "Java Version"
This will make the curse client find the right version of Java therefore fixing the error.
Note: if only Forge loads up, you might wanna search for the modpack folder that contains all the mods and replace by the one that's empty.