1.7.6 is the last version not crashing on my server. I tried several forge version >=1230, but server keep crashing when I try to connect. Maybe an incompatibility between Thaumcraft and Abyssalcraft >1.7.6?

Caused by: java.lang.NullPointerException
        at thaumcraft.common.lib.events.EventHandlerEntity.doRepair(EventHandlerEntity.java:177) ~[EventHandlerEntity.class:?]

full logs: https://gist.githubusercontent.com/soratobukuroneko/28246ca40bff6caa2a56/raw/latest.log

There's a known enchantment ID conflict between AbyssalCraft 1.7.8.1 and thaumcraft. Right now the only solution is to change the IDs in the thaumcraft config file.