diff --git a/src/backend/langflow/graph/vertex/base.py b/src/backend/langflow/graph/vertex/base.py
index 3877e59b1..51fa8d815 100644
--- a/src/backend/langflow/graph/vertex/base.py
+++ b/src/backend/langflow/graph/vertex/base.py
@@ -185,9 +185,10 @@ class Vertex:
                 # Load the type in value.get('suffixes') using
                 # what is inside value.get('content')
                 # value.get('value') is the file name
-                file_path = value.get("file_path")
-
-                params[key] = file_path
+                if file_path := value.get("file_path"):
+                    params[key] = file_path
+                else:
+                    raise ValueError(f"File path not found for {self.vertex_type}")
             elif value.get("type") in DIRECT_TYPES and params.get(key) is None:
                 if value.get("type") == "code":
                     try:
diff --git a/src/backend/langflow/interface/importing/utils.py b/src/backend/langflow/interface/importing/utils.py
index d07222dd1..000eed205 100644
--- a/src/backend/langflow/interface/importing/utils.py
+++ b/src/backend/langflow/interface/importing/utils.py
@@ -144,6 +144,8 @@ def import_chain(chain: str) -> Type[Chain]:
 
     if chain in CUSTOM_CHAINS:
         return CUSTOM_CHAINS[chain]
+    if chain == "SQLDatabaseChain":
+        return import_class("langchain_experimental.sql.SQLDatabaseChain")
     return import_class(f"langchain.chains.{chain}")
 
 
diff --git a/src/backend/langflow/services/cache/manager.py b/src/backend/langflow/services/cache/manager.py
index 19f5034cf..da76a2b5c 100644
--- a/src/backend/langflow/services/cache/manager.py
+++ b/src/backend/langflow/services/cache/manager.py
@@ -74,13 +74,17 @@ class InMemoryCache(BaseCacheService, Service):
             ):
                 # Move the key to the end to make it recently used
                 self._cache.move_to_end(key)
-                unpickled = pickle.loads(item["value"])
-                return unpickled
+                # Check if the value is pickled
+                if isinstance(item["value"], bytes):
+                    value = pickle.loads(item["value"])
+                else:
+                    value = item["value"]
+                return value
             else:
                 self.delete(key)
         return None
 
-    def set(self, key, value):
+    def set(self, key, value, pickle=False):
         """
         Add an item to the cache.
 
@@ -98,8 +102,10 @@ class InMemoryCache(BaseCacheService, Service):
                 # Remove least recently used item
                 self._cache.popitem(last=False)
             # pickle locally to mimic Redis
-            pickled = pickle.dumps(value)
-            self._cache[key] = {"value": pickled, "time": time.time()}
+            if pickle:
+                value = pickle.dumps(value)
+
+            self._cache[key] = {"value": value, "time": time.time()}
 
     def upsert(self, key, value):
         """
diff --git a/src/backend/langflow/services/cache/utils.py b/src/backend/langflow/services/cache/utils.py
index a708c6e7e..bd6b4fb0a 100644
--- a/src/backend/langflow/services/cache/utils.py
+++ b/src/backend/langflow/services/cache/utils.py
@@ -207,5 +207,7 @@ def save_uploaded_file(file: UploadFile, folder_name):
 
 def update_build_status(cache_service, flow_id: str, status: BuildStatus):
     cached_flow = cache_service[flow_id]
+    if cached_flow is None:
+        raise ValueError(f"Flow {flow_id} not found in cache")
     cached_flow["status"] = status
     cache_service[flow_id] = cached_flow
diff --git a/src/backend/langflow/template/frontend_node/documentloaders.py b/src/backend/langflow/template/frontend_node/documentloaders.py
index 8118593f3..0be2ebe98 100644
--- a/src/backend/langflow/template/frontend_node/documentloaders.py
+++ b/src/backend/langflow/template/frontend_node/documentloaders.py
@@ -171,7 +171,7 @@ class DocumentLoaderFrontNode(FrontendNode):
         self.template.add_field(
             TemplateField(
                 field_type="dict",
-                required=True,
+                required=False,
                 show=True,
                 name="metadata",
                 value={},