diff --git a/userspace/engine/formats.cpp b/userspace/engine/formats.cpp
index 7be6eaab..217cd15e 100644
--- a/userspace/engine/formats.cpp
+++ b/userspace/engine/formats.cpp
@@ -81,7 +81,8 @@ int falco_formats::format_event (lua_State *ls)
 	    !lua_isstring(ls, -2) ||
 	    !lua_isstring(ls, -3) ||
 	    !lua_islightuserdata(ls, -4)) {
-		throw falco_exception("Invalid arguments passed to format_event()\n");
+		lua_pushstring(ls, "Invalid arguments passed to format_event()");
+		lua_error(ls);
 	}
 	sinsp_evt* evt = (sinsp_evt*)lua_topointer(ls, 1);
 	const char *rule = (char *) lua_tostring(ls, 2);
diff --git a/userspace/engine/rules.cpp b/userspace/engine/rules.cpp
index 63b9b416..cec545ec 100644
--- a/userspace/engine/rules.cpp
+++ b/userspace/engine/rules.cpp
@@ -49,7 +49,8 @@ int falco_rules::clear_filters(lua_State *ls)
 {
 	if (! lua_islightuserdata(ls, -1))
 	{
-		throw falco_exception("Invalid arguments passed to clear_filters()\n");
+		lua_pushstring(ls, "Invalid arguments passed to clear_filters()");
+		lua_error(ls);
 	}
 
 	falco_rules *rules = (falco_rules *) lua_topointer(ls, -1);
@@ -70,7 +71,8 @@ int falco_rules::add_filter(lua_State *ls)
 	    ! lua_istable(ls, -2) ||
 	    ! lua_istable(ls, -1))
 	{
-		throw falco_exception("Invalid arguments passed to add_filter()\n");
+		lua_pushstring(ls, "Invalid arguments passed to add_filter()");
+		lua_error(ls);
 	}
 
 	falco_rules *rules = (falco_rules *) lua_topointer(ls, -4);
@@ -122,7 +124,8 @@ int falco_rules::enable_rule(lua_State *ls)
 	    ! lua_isstring(ls, -2) ||
 	    ! lua_isnumber(ls, -1))
 	{
-		throw falco_exception("Invalid arguments passed to enable_rule()\n");
+		lua_pushstring(ls, "Invalid arguments passed to enable_rule()");
+		lua_error(ls);
 	}
 
 	falco_rules *rules = (falco_rules *) lua_topointer(ls, -3);