[1.7.10] Forge Server doesnt work (crash)

Hey Guys,

I tried to install a Forge 1.7.10 Server on my Linux vserver (its NOT a dedicated game server). But every time somebody joins, it crash.

I have made the server following this tutorial: https://www.youtube.com/watch?v=-9WEY1Dbtiw

My 1.8.9 Server i´ve made before just worked fine.

Used mods are: Security Craft, Advanced Lightsabers

below ill post the crash report, and a video of the server starting (subtitles/comments are german, ´cause it was made for german forum).

Video of Server starting (with some erros at the end):  https://youtu.be/NvRvxP0lK_c

(translation: "server läuft" = server is running; "ich (versuche zu) joinen" = i (try to) join)

Crash Report: https://pastebin.com/KkDSrAYL