diff --git a/pipelinerl/preprocess.py b/pipelinerl/preprocess.py
index 65e29b4b..382458ca 100644
--- a/pipelinerl/preprocess.py
+++ b/pipelinerl/preprocess.py
@@ -160,7 +160,18 @@ def preprocess_dataset(
         entry["step_index"] = entry["metadata"]["step_index"]
     if not isinstance(tokenizer.eos_token_id, int):
         raise ValueError(f"Tokenizer {tokenizer} does not have an eos_token_id")
-    dataset = populate_rl_data(dataset=dataset, eos_token_id=tokenizer.eos_token_id, config=rl_config)
+    try:
+        dataset = populate_rl_data(dataset=dataset, eos_token_id=tokenizer.eos_token_id, config=rl_config)
+    except Exception as e:
+        logger.error(f"Error in populate_rl_data: {e}")
+        logger.error(f"Data: {data}")
+        logger.error(f"Dataset: {dataset}")
+        logger.error(f"Tokenizer: {tokenizer}")
+        logger.error(f"Tokenizer eos_token_id: {tokenizer.eos_token_id}")
+        logger.error(f"RL config: {rl_config}")
+        logger.error(f"LLM: {llm}")
+        logger.error(f"Seq length: {seq_length}")
+        raise e
     return dataset
 
 
@@ -533,7 +544,7 @@ def run_preprocessing_loop(
                     while len(buffer) > 0:
                         if len(processed_entries_queue) == processed_entries_queue.maxlen:
                             if not pop_old_data:
-                                break 
+                                break
                             else:
                                 processed_entries_queue_popped_data += 1
                                 if processed_entries_queue_popped_data % 100 == 0 and last_time_notice != processed_entries_queue_popped_data // 100:
@@ -573,6 +584,10 @@ def run_preprocessing_loop(
                                     sample_length = len(entry["input_ids"])
 
                                     if current_length + sample_length > cfg.finetune.seq_length:
+                                        if len(current_batch) == 0:
+                                            raise ValueError(
+                                                f"sample_length is {sample_length}, but cfg.finetune.seq_length is {cfg.finetune.seq_length}"
+                                            )
                                         time_to_write = True
                                         break  # Current micro batch is full