Mod version: v1.5.0-pre199_73_mc1.12.2
Server: last Mohist 1.12.2
Crashlog:
`---- Minecraft Crash Report ----
// I'm sorry, Dave.

Time: 2020-12-24 10:02:47 UTC
Description: Exception in server tick loop

net.minecraftforge.fml.common.LoaderExceptionModCrash: Caught exception from OnlinePictureFrame (opframe)
Caused by: java.lang.NoClassDefFoundError: com/creativemd/opf/OPFrame$1
at com.creativemd.opf.OPFrame.loadLittleTiles(OPFrame.java:97)
at com.creativemd.opf.OPFrame.preInit(OPFrame.java:66)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at net.minecraftforge.fml.common.FMLModContainer.handleModStateEvent(FMLModContainer.java:632)
at sun.reflect.GeneratedMethodAccessor2.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.google.common.eventbus.Subscriber.invokeSubscriberMethod(Subscriber.java:91)
at com.google.common.eventbus.Subscriber$SynchronizedSubscriber.invokeSubscriberMethod(Subscriber.java:150)
at com.google.common.eventbus.Subscriber$1.run(Subscriber.java:76)
at com.google.common.util.concurrent.MoreExecutors$DirectExecutor.execute(MoreExecutors.java:399)
at com.google.common.eventbus.Subscriber.dispatchEvent(Subscriber.java:71)
at com.google.common.eventbus.Dispatcher$PerThreadQueuedDispatcher.dispatch(Dispatcher.java:116)
at com.google.common.eventbus.EventBus.post(EventBus.java:217)
at net.minecraftforge.fml.common.LoadController.sendEventToModContainer(LoadController.java:215)
at net.minecraftforge.fml.common.LoadController.propogateStateMessage(LoadController.java:193)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.google.common.eventbus.Subscriber.invokeSubscriberMethod(Subscriber.java:91)
at com.google.common.eventbus.Subscriber$SynchronizedSubscriber.invokeSubscriberMethod(Subscriber.java:150)
at com.google.common.eventbus.Subscriber$1.run(Subscriber.java:76)
at com.google.common.util.concurrent.MoreExecutors$DirectExecutor.execute(MoreExecutors.java:399)
at com.google.common.eventbus.Subscriber.dispatchEvent(Subscriber.java:71)
at com.google.common.eventbus.Dispatcher$PerThreadQueuedDispatcher.dispatch(Dispatcher.java:116)
at com.google.common.eventbus.EventBus.post(EventBus.java:217)
at net.minecraftforge.fml.common.LoadController.distributeStateMessage(LoadController.java:132)
at net.minecraftforge.fml.common.Loader.preinitializeMods(Loader.java:632)
at net.minecraftforge.fml.server.FMLServerHandler.beginServerLoading(FMLServerHandler.java:102)
at net.minecraftforge.fml.common.FMLCommonHandler.onServerStart(FMLCommonHandler.java:329)
at net.minecraft.server.dedicated.DedicatedServer.init(DedicatedServer.java:171)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:593)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.ClassNotFoundException: com.creativemd.opf.OPFrame$1
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:191)
at java.lang.ClassLoader.loadClass(ClassLoader.java:418)
at java.lang.ClassLoader.loadClass(ClassLoader.java:351)
... 37 more
Caused by: java.lang.NoClassDefFoundError: com/creativemd/littletiles/client/gui/handler/LittleGuiHandler
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:756)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:182)
... 39 more
Caused by: java.lang.ClassNotFoundException: com.creativemd.littletiles.client.gui.handler.LittleGuiHandler
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:101)
at java.lang.ClassLoader.loadClass(ClassLoader.java:418)
at java.lang.ClassLoader.loadClass(ClassLoader.java:351)
... 43 more`

Update OnlinePictureFrame (you need the newest beta).