Go into "Windows" folder, then PokemonEmerald folder, then Binaries, Win64 and run as administrator PokemonEmerald.exe. It worked for me.
Not even that worked.
after first error i got this 2nd error message:
Fatal error: [File:D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Private\Windows\WindowsPlatformMisc.cpp] [Line: 439]
Pure virtual function being called
0x00007ff813b759e4 VCRUNTIME140.dll!UnknownFunction []
0x00007ff77c18e16a PokemonEmerald.exe!UE::Shader::FPreshaderData::EvaluateConstant() []
0x00007ff77c18e501 PokemonEmerald.exe!UE::Shader::EvaluatePreshader() []
0x00007ff77bb3cc4b PokemonEmerald.exe!FUniformExpressionSet::FillUniformBuffer() []
0x00007ff77baa8234 PokemonEmerald.exe!`FUniformExpressionCacheAsyncUpdater::Update'::`2'::<lambda_1>::operator()() []
0x00007ff77599faa3 PokemonEmerald.exe!TGraphTask<TFunctionGraphTaskImpl<void __cdecl(void),0> >::ExecuteTask() []
0x00007ff775902278 PokemonEmerald.exe!`LowLevelTasks::FTask::Init<`FTaskGraphCompatibilityImplementation::QueueTask'::`5'::<lambda_1> >'::`11'::<lambda_1>::operator()() []
0x00007ff7759098c3 PokemonEmerald.exe!LowLevelTasks::TTaskDelegate<LowLevelTasks::FTask * __ptr64 __cdecl(bool),48>::TTaskDelegateImpl<`LowLevelTasks::FTask::Init<`FTaskGraphCompatibilityImplementation::QueueTask'::`5'::<lambda_1> >'::`11'::<lambda_1>,0>::CallAndMove() []
0x00007ff775917c9e PokemonEmerald.exe!LowLevelTasks::FTask::ExecuteTask() []
0x00007ff775917a17 PokemonEmerald.exe!LowLevelTasks::FScheduler::ExecuteTask() []
0x00007ff7758fac02 PokemonEmerald.exe!LowLevelTasks::FScheduler::TryExecuteTaskFrom<LowLevelTasks::TLocalQueueRegistry<1024>::TLocalQueue,&LowLevelTasks::TLocalQueueRegistry<1024>::TLocalQueue::DequeueGlobal,0>() []
0x00007ff77593ced2 PokemonEmerald.exe!LowLevelTasks::FScheduler::WorkerMain() []
0x00007ff7759075a0 PokemonEmerald.exe!UE::CompressedBuffer::Private::FHeader::CalculateCrc32() []
0x00007ff775adfdf3 PokemonEmerald.exe!FThreadImpl::Run() []
0x00007ff775ee18b2 PokemonEmerald.exe!FRunnableThreadWin::Run() []
0x00007ff775ed5307 PokemonEmerald.exe!FRunnableThreadWin::GuardedRun() []
0x00007ff83f5ae8d7 KERNEL32.DLL!UnknownFunction []
Crash in runnable thread Foreground Worker #1