Need help with an error that I have no idea how to fix

[OmenPM]

Need help with an error

I have a custom modpack that I have made, my other friends have been able to play it without a problem.

However one of my friends is unable to run the modpack. From my understanding, the modpack loads and tries to open the MC client, is unable to open the MC client, and crashes back to Technic launcher. He has a 64 bit version of Java and is allowing Technic launcher GB of RAM (my modpack uses usually 1.5GB max)

My modpack: https://www.technicpack.net/modpack/godsquad-pack.1577263

The full crash report my friend gave me: https://pastebin.com/Fht29Bsa

[JaariAtmc]

Tell them to downgrade their Java to 8u51. They can always use the java used by the vanilla minecraft launcher. They'll just have to find it.