@@ -1476,14 +1476,14 @@ int tr_eval_string(struct sip_msg *msg, tr_param_t *tp, int subtype,

 				if(pv_get_spec_value(msg, (pv_spec_p)tp->next->v.data, &v)!=0

 						|| (!(v.flags&PV_VAL_INT)))

 				{

-					LM_ERR("fmt cannot get p2 (cfg line: %d)\n",

+					LM_ERR("fmtline cannot get p2 (cfg line: %d)\n",

 							get_cfg_crt_line());

 					return -1;

 				}

 				m = v.ri;

 			}

-			if(n<0 || m<0) {

-				LM_ERR("substr negative offset (cfg line: %d)\n",

+			if(n<=0 || m<0) {

+				LM_ERR("fmtline with invalid parameters (cfg line: %d)\n",

 						get_cfg_crt_line());

 				return -1;

 			}