Add handling for missing VAE files

When a model has a VAE configured but the VAE files don't exist in
the repository, try loading with the default VAE instead.

videogen.py

@@ -8253,6 +8253,25 @@ def main(args):
             # Some models have files in subdirectories (e.g., diffusers/) or use different structures
             is_404_error = "404" in error_str or "Entry Not Found" in error_str or "not found" in error_str.lower()
             
+            # Check if this is a VAE file not found error
+            is_vae_error = "diffusion_pytorch_model" in error_str and "vae" in error_str.lower()
+            
+            if is_vae_error:
+                print(f"\n⚠️  VAE file not found in model repository")
+                print(f"   Attempting to load without custom VAE (using default)...")
+                # Try loading with default VAE by removing any custom VAE
+                vae_pipe_kwargs = pipe_kwargs.copy()
+                if "vae" in vae_pipe_kwargs:
+                    del vae_pipe_kwargs["vae"]
+                try:
+                    pipe = PipelineClass.from_pretrained(model_id_to_load, **vae_pipe_kwargs)
+                    print(f"  ✅ Successfully loaded with default VAE")
+                    pipeline_loaded_successfully = True
+                except Exception as vae_e:
+                    print(f"  ❌ Also failed with default VAE: {vae_e}")
+                    error_str = str(vae_e)
+                    is_404_error = "404" in error_str or "Entry Not Found" in error_str or "not found" in error_str.lower()
+            
             if is_404_error and "model_index.json" in error_str:
                 print(f"\n⚠️  model_index.json not found at root level")
                 print(f"   Attempting alternative loading strategies...")