diff --git a/HISTORY b/HISTORY
index 1f80dc1..cabf1a2 100755
--- a/HISTORY
+++ b/HISTORY
@@ -1,4 +1,5 @@
 Jan. 9 2016
+Developing lambda, improved error handling
 Developing lambda, fixed an issue with only a PRINT statement
 
 Jan. 8 2016
diff --git a/core/my_basic.c b/core/my_basic.c
index a84f620..6ba8b9c 100755
--- a/core/my_basic.c
+++ b/core/my_basic.c
@@ -259,6 +259,7 @@ static const char* _ERR_DESC[] = {
 	"Class expected",
 	"Duplicate class",
 	"Wrong meta class",
+	"Invalid lambda",
 	"Collection expected",
 	"Iterator expected",
 	"Collection or iterator expected",
@@ -1410,6 +1411,7 @@ static int _remove_filled_upvalue(void* data, void* extra, void* u);
 static int _fill_outer_scope(void* data, void* extra, void* t);
 static _running_context_t* _link_lambda_scope_chain(mb_interpreter_t* s, _lambda_t* lambda, bool_t weak);
 static _running_context_t* _unlink_lambda_scope_chain(mb_interpreter_t* s, _lambda_t* lambda, bool_t weak);
+static bool_t _is_valid_lambda_body_node(mb_interpreter_t* s, _lambda_t* lambda, _object_t* obj);
 #endif /* MB_ENABLE_LAMBDA */
 #ifdef MB_ENABLE_CLASS
 static _running_context_t* _reference_scope_by_class(mb_interpreter_t* s, _running_context_t* p, _class_t* c);
@@ -6407,6 +6409,15 @@ _running_context_t* _unlink_lambda_scope_chain(mb_interpreter_t* s, _lambda_t* l
 
 	return lambda->scope;
 }
+
+bool_t _is_valid_lambda_body_node(mb_interpreter_t* s, _lambda_t* lambda, _object_t* obj) {
+	/* Check whether an object is a valid lambda body node */
+	return
+		!_IS_FUNC(obj, _core_def) &&
+		!_IS_FUNC(obj, _core_enddef) &&
+		!_IS_FUNC(obj, _core_class) &&
+		!_IS_FUNC(obj, _core_endclass);
+}
 #endif /* MB_ENABLE_LAMBDA */
 
 #ifdef MB_ENABLE_CLASS
@@ -11936,6 +11947,9 @@ int _core_lambda(mb_interpreter_t* s, void** l) {
 
 		if(!routine->func.lambda.parameters)
 			routine->func.lambda.parameters = _ls_create();
+		if(!v || ((_object_t*)v)->type != _DT_VAR) {
+			_handle_error_on_obj(s, SE_RN_INVALID_LAMBDA, 0, TON(l), MB_FUNC_ERR, _error, result);
+		}
 		var = ((_object_t*)v)->data.variable;
 
 		/* Add lambda parameters */
@@ -11979,6 +11993,10 @@ int _core_lambda(mb_interpreter_t* s, void** l) {
 		else if(_IS_FUNC(ast->data, _core_close_bracket))
 			brackets--;
 
+		if(ast && !_is_valid_lambda_body_node(s, &routine->func.lambda, (_object_t*)ast->data)) {
+			_handle_error_on_obj(s, SE_RN_INVALID_LAMBDA, 0, TON(l), MB_FUNC_ERR, _error, result);
+		}
+
 		/* Mark upvalues */
 		if(ast)
 			_try_mark_upvalue(s, routine, (_object_t*)ast->data);
diff --git a/core/my_basic.h b/core/my_basic.h
index 607ce77..a66ad9b 100755
--- a/core/my_basic.h
+++ b/core/my_basic.h
@@ -329,6 +329,7 @@ typedef enum mb_error_e {
 	SE_RN_CLASS_EXPECTED,
 	SE_RN_DUPLICATE_CLASS,
 	SE_RN_WRONG_META_CLASS,
+	SE_RN_INVALID_LAMBDA,
 	SE_RN_COLLECTION_EXPECTED,
 	SE_RN_ITERATOR_EXPECTED,
 	SE_RN_COLLECTION_OR_ITERATOR_EXPECTED,
diff --git a/output/my_basic_mac b/output/my_basic_mac
index 14d798c..845f2f3 100755
Binary files a/output/my_basic_mac and b/output/my_basic_mac differ