Error message shows up whenever i start server

[ProtocolLib] INTERNAL ERROR: Cannot compile structure. Disabing compiler.

[ERROR]: [ProtocolLib] INTERNAL ERROR: Cannot compile structure. Disabing compiler.
If this problem hasn't already been reported, please open a ticket
at https://github.com/dmulloy2/ProtocolLib/issues with the following data:
Stack Trace:
java.lang.reflect.InaccessibleObjectException: Unable to make protected final java.lang.Class java.lang.ClassLoader.defineClass(java.lang.String,byte[],int,int) throws java.lang.ClassFormatError accessible: module java.base does not "opens java.lang" to unnamed module @518eed6f
at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:357)
at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:297)
at java.base/java.lang.reflect.Method.checkCanSetAccessible(Method.java:199)
at java.base/java.lang.reflect.Method.setAccessible(Method.java:193)
at com.comphenix.protocol.reflect.compiler.StructureCompiler.generateClass(StructureCompiler.java:299)
at com.comphenix.protocol.reflect.compiler.StructureCompiler.compile(StructureCompiler.java:213)
at com.comphenix.protocol.reflect.compiler.BackgroundCompiler$2.call(BackgroundCompiler.java:204)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630)
at java.base/java.lang.Thread.run(Thread.java:831)
Dump:
Parameters:
com.comphenix.protocol.reflect.StructureModifier@5c6794b2[
targetType=class net.minecraft.server.v1_16_R3.NBTTagCompound
target=
converter=
fieldType=interface java.util.Map
data=[public final java.util.Map net.minecraft.server.v1_16_R3.NBTTagCompound.map]
defaultFields={}
subtypeCache={}
customConvertHandling=false
useStructureCompiler=true
]
manager:
com.comphenix.protocol.injector.PacketFilterManager@2065014d[
unhookTask=com.comphenix.protocol.injector.DelayedSingleTask@278f04ab
packetListeners=[PacketAdapter[plugin=LibsDisguises, sending=ListeningWhitelist[priority=NORMAL, packets=[NAMED_SOUND_EFFECT[class=PacketPlayOutNamedSoundEffect, id=81], ENTITY_STATUS[class=PacketPlayOutEntityStatus, id=26]], gamephase=PLAYING, options=[]], receiving=EMPTY_WHITELIST], PacketAdapter[plugin=LibsDisguises, sending=ListeningWhitelist[priority=HIGH, packets=[ATTACH_ENTITY[class=PacketPlayOutAttachEntity, id=69], ANIMATION[class=PacketPlayOutAnimation, id=5], NAMED_ENTITY_SPAWN[class=PacketPlayOutNamedEntitySpawn, id=4], ENTITY_METADATA[class=PacketPlayOutEntityMetadata, id=68], REL_ENTITY_MOVE[class=PacketPlayOutRelEntityMove, id=39], ENTITY_EQUIPMENT[class=PacketPlayOutEntityEquipment, id=71], ENTITY_VELOCITY[class=PacketPlayOutEntityVelocity, id=70], ENTITY_LOOK[class=PacketPlayOutEntityLook, id=41], REL_ENTITY_MOVE_LOOK[class=PacketPlayOutRelEntityMoveLook, id=40], ENTITY_TELEPORT[class=PacketPlayOutEntityTeleport, id=86], ENTITY_EFFECT[class=PacketPlayOutEntityEffect, id=89], UPDATE_ATTRIBUTES[class=PacketPlayOutUpdateAttributes, id=88], ENTITY_HEAD_ROTATION[class=PacketPlayOutEntityHeadRotation, id=58], ENTITY_STATUS[class=PacketPlayOutEntityStatus, id=26]], gamephase=PLAYING, options=[]], receiving=EMPTY_WHITELIST], PacketAdapter[plugin=LibsDisguises, sending=ListeningWhitelist[priority=HIGH, packets=[WINDOW_ITEMS[class=PacketPlayOutWindowItems, id=19], SET_SLOT[class=PacketPlayOutSetSlot, id=21], WINDOW_CLICK[class=PacketPlayInWindowClick, id=9], SET_CREATIVE_SLOT[class=PacketPlayInSetCreativeSlot, id=40], HELD_ITEM_SLOT[class=PacketPlayInHeldItemSlot, id=37]], gamephase=PLAYING, options=[]], receiving=ListeningWhitelist[priority=HIGH, packets=[WINDOW_ITEMS[class=PacketPlayOutWindowItems, id=19], SET_SLOT[class=PacketPlayOutSetSlot, id=21], WINDOW_CLICK[class=PacketPlayInWindowClick, id=9], SET_CREATIVE_SLOT[class=PacketPlayInSetCreativeSlot, id=40], HELD_ITEM_SLOT[class=PacketPlayInHeldItemSlot, id=37]], gamephase=PLAYING, options=[]]]]
packetInjector=com.comphenix.protocol.injector.netty.ProtocolInjector$5@472dc6ec
playerInjection=com.comphenix.protocol.injector.netty.ProtocolInjector$4@1a791973
inputBufferedPackets=[]
recievedListeners=com.comphenix.protocol.injector.SortedPacketListenerList@129e0c18
sendingListeners=com.comphenix.protocol.injector.SortedPacketListenerList@4d6bf8bc
hasClosed=false
classLoader=PluginClassLoader{plugin=ProtocolLib v4.6.0, pluginEnabled=true, url=plugins\ProtocolLib.jar}
reporter=com.comphenix.protocol.ProtocolLib$1@36b87222
server=CraftServer{serverName=Paper,serverVersion=git-Paper-670,minecraftVersion=1.16.5}
library=ProtocolLib v4.6.0
asyncFilterManager=com.comphenix.protocol.async.AsyncFilterManager@4618ea11
knowsServerPackets=true
knowsClientPackets=true
phaseLoginCount=0
phasePlayingCount=4
packetCreation=false
nettyInjector=com.comphenix.protocol.injector.netty.ProtocolInjector@627afd9d
pluginVerifier=com.comphenix.protocol.injector.PluginVerifier@605c607b
hasRecycleDistance=true
minecraftVersion=(MC: 1.16.5)
debug=false
]
Sender:
com.comphenix.protocol.reflect.compiler.BackgroundCompiler@758bd447[
listeners={com.comphenix.protocol.reflect.compiler.StructureCompiler$StructureKey@df4d1305=[com.comphenix.protocol.reflect.compiler.BackgroundCompiler$1@899aee5], com.comphenix.protocol.reflect.compiler.StructureCompiler$StructureKey@882abca1=[com.comphenix.protocol.reflect.compiler.BackgroundCompiler$1@3dba3c7e]}
listenerLock=java.lang.Object@3e66dc0a
compiler=com.comphenix.protocol.reflect.compiler.StructureCompiler@15640e6d
enabled=false
shuttingDown=false
executor=java.util.concurrent.Executors$FinalizableDelegatedExecutorService@50cf74a2
reporter=com.comphenix.protocol.ProtocolLib$1@36b87222
unknownPermGenBean=java.lang.Object@3c7afb09
permGenBean=
disablePermGenFraction=0.65
]
Version:
ProtocolLib v4.6.0
Java Version:
16.0.1
Server:
git-Paper-670 (MC: 1.16.5)

Expected behavior
Not for this to show up

Version Info
dump-2021-06-30_19.45.05.txt

Agreed. Looks like the newest version made it. I also have this error. Gonna change to the older version.

This is fixed in the latest dev builds. Find them here: https://ci.dmulloy2.net/job/ProtocolLib/