diff --git a/config_schema.json b/config_schema.json
index 67c4f27..930f79a 100644
--- a/config_schema.json
+++ b/config_schema.json
@@ -464,7 +464,7 @@
                             "enum": ["EqualsTo", "StartsWith", "EndsWith", "Contains", "RegexMatch"]
                           },
                           "input":{
-                            "description": "Content used to run the matchType above against the received header value; i.e., received header value should either equal to or start with or end with or contain the content specified in this field; if RegexMatch is chosen, it means this input field is a regular expression in ECMAScript grammar, and it should match the entire target character sequence, i.e., the header value",
+                            "description": "Content used to run the matchType above against the received header value; i.e., received header value should either equal to or start with or end with or contain the content specified in this field; if RegexMatch is chosen, it means this input field is a regular expression of ECMAScript flavor, and it should match the entire target character sequence, i.e., the header value",
                             "default": "200",
                             "type":"string"
                           }
@@ -489,7 +489,7 @@
                             "enum": ["EqualsTo", "StartsWith", "EndsWith", "Contains", "RegexMatch"]
                           },
                           "input": {
-                            "description": "Content used to execute the matchType above against the value specified by the Json pointer above; the value specified by the Json pointer above should either equal to or start with or end with or contain the content specified in this field; if RegexMatch is chosen, it means this input field is a regular expression in ECMAScript grammar, and it should match the entire target character sequence, i.e., the value specified by the Json pointer",
+                            "description": "Content used to execute the matchType above against the value specified by the Json pointer above; the value specified by the Json pointer above should either equal to or start with or end with or contain the content specified in this field; if RegexMatch is chosen, it means this input field is a regular expression of ECMAScript flavor, and it should match the entire target character sequence, i.e., the value specified by the Json pointer",
                             "type":"string"
                           }
                         }
@@ -499,7 +499,7 @@
                 },
                 "value-pickers":
                 {
-                  "description": "This is the actions to run when the response is received; it is using a regular expression to pick up a value, from a specific header, or from a value in the payload specified by a Json pointer, and then save the value to a variable whose name is given in save-to-variable; the stored value can be accessed later by wrapping the name of the variable with ${}, for example, pick up a value from the response header here, and store it to a variable named user_id, and then refer to this variable in a later request of the same scenario in this way: some_api_path/${user_id}, and ${user_id} would be replaced by the actual value stored here",
+                  "description": "This is the actions to run when the response is received; it is using a regular expression of ECMAScript flavor to pick up a value, from a specific header, or from a value in the payload specified by a Json pointer, and then save the value to a variable whose name is given in save-to-variable; the stored value can be accessed later by wrapping the name of the variable with ${}, for example, pick up a value from the response header here, and store it to a variable named user_id, and then refer to this variable in a later request of the same scenario in this way: some_api_path/${user_id}, and ${user_id} would be replaced by the actual value stored here",
                   "type": "array",
                   "items": {
                     "type": "object",
@@ -515,7 +515,8 @@
                         "description": "A header name, or a Json pointer, depending on what is given in where-to-pickup-from"
                       },
                       "regexp": {
-                        "description": "A regular expression to extract value from the source above",
+                        "description": "A regular expression of ECMAScript flavor to extract value from the source above",
+                        "default": ".*",
                         "type":"string"
                       },
                       "save-to-variable": {
diff --git a/h2load_utils.cc b/h2load_utils.cc
index 3f521cf..0335eb6 100644
--- a/h2load_utils.cc
+++ b/h2load_utils.cc
@@ -1536,8 +1536,9 @@ void post_process_json_config_schema(h2load::Config& config)
 
     for (auto& scenario : config.json_config_schema.scenarios)
     {
-        for (auto& request : scenario.requests)
+        for (auto i = 0; i < scenario.requests.size(); i++)
         {
+            auto& request = scenario.requests[i];
 
             for (auto& schema_header_match : request.response_match.header_match)
             {
@@ -1561,12 +1562,20 @@ void post_process_json_config_schema(h2load::Config& config)
                 {
                     request.make_request_function_present = true;
                 }
+                else
+                {
+                    std::cerr << scenario.name<<"_"<<i<<": lua script provided, but function " << make_request <<" is either malformed, or not present"<<std::endl;
+                }
                 lua_settop(L, 0);
                 lua_getglobal(L, validate_response);
                 if (lua_isfunction(L, -1))
                 {
                     request.validate_response_function_present = true;
                 }
+                else
+                {
+                    std::cerr << scenario.name<<"_"<<i<<": lua script provided, but function " << validate_response <<" is either malformed, or not present"<<std::endl;
+                }
                 lua_settop(L, 0);
                 lua_close(L);
             }