diff --git a/interpol_param.pro b/interpol_param.pro
index 350aaf96cd1ddf9838309e39591f726902be6ae7..12fb108128a2ea355907ff9fc71fb139ad67b46a 100644
--- a/interpol_param.pro
+++ b/interpol_param.pro
@@ -14,6 +14,11 @@ function interpol_param, table, par_name, date, empty_params = empty_params
 	par_val = par_val[s]
 	par_date = par_date[s]
 	jul_date = date_conv(date, 'JULIAN')
-	if jul_date ge min(par_date) and jul_date le max(par_date) then value = interpol(float(par_val), par_date, jul_date) else value = 0.0
+	if jul_date ge min(par_date) and jul_date le max(par_date) then value = interpol(float(par_val), par_date, jul_date) else begin
+		; value = 0.0
+		journal, 'Error 01: parameter not found in house-keeping dump table.'
+		journal
+		exit, status = 1
+	endelse
 	if finite(value) then return, value else return, 0.0
 end