Version: Latest Release, 1.8.06
Issue: Server crashes before finishing startup.

CrashReport/Log:
ServerCrashLog.txt

ModPack/ModList:

Edit: I know IItemRenderer Reborn isn't listed in the modlist, but the error still persists with it installed.

silkspawners 1.8.06 requires evil notch lib snapshot 80 which has builtin iitemrenderer and requires no other dependencies. Since evil notch lib is outdated other mods using it will crash.

I recommend using latest betas as they are close to releases, have alot of more work and fixes put into them. But, are not themsleves as stable as the releases and, the releases are very outdated recently

which leads to your modlist of [classwriter-1.2,evil notch lib(snapshot 96), iitemrenderer-reborn-0.9.3,silkspawners(latest)]

Replaced all mods with latest Betas, still crashes. But with a new error log.
latest.log

make sure you have sponge forge installed it sounds like silkspawners is unable to run due to the asm not firing.

if the issue still persists open up a new issue called crashing with sponge

Yes SpongeForge is installed and works with the 3 plugins that run on it