[main] Fix error message handling.

Author: tomhrr

lib/nrtm.ch

@@ -157,18 +157,19 @@ nrtm._servers var; nrtm._servers !;
     "-g {}:3:{}-{}\n" fmt; 1 mlist;
     server @; port @; nc;
     gen var!;
-    gen @; ["^%START " m] beforei; r; pop; chomp;
-    dup; ERROR m; if;
-        "failed query: {}" fmt; error;
-    then;
-    dup; "START Version: \d+ (.+?) (\d+?)-(\d+)$" c;
-    start var!;
-    start @; len; 0 =; if;
-        "did not see response header: got '{}' instead" fmt; error;
+    gen @; ["^%START " m] beforei; r; prelude var!;
+    prelude @; pop; chomp;
+    "START Version: \d+ .+? \d+-\d+$" m; if;
+        gen @;
+        nrtm._query-gen;
     else;
-        drop;
+        prelude @; [^% m] first;
+        dup; is-null; if;
+            drop;
+            "did not see response header" error;
+        then;
+        chomp;
+        "did not see response header: got '{}' instead" fmt; error;
     then;
-    gen @;
-    nrtm._query-gen;
     ,,