diff --git a/checkin_notes b/checkin_notes
index 1e0114d379..792f94a4f0 100644
--- a/checkin_notes
+++ b/checkin_notes
@@ -3780,3 +3780,11 @@ David  19 May 2010
 
     client/
         boinc_cmd.cpp
+
+David  19 May 2010
+    - GUI RPC: improved error reporting
+
+    lib/
+        gui_rpc_client_ops.cpp
+    html/ops/
+        credit.php
diff --git a/html/ops/credit.php b/html/ops/credit.php
index 99a919a811..d7c8c43cb4 100644
--- a/html/ops/credit.php
+++ b/html/ops/credit.php
@@ -8,9 +8,16 @@ require_once("../inc/boinc_db.inc");
 
 define('COBB_SCALE', 200/86400e9);
 
+function gavid($avid, $appid) {
+    if ($avid < 0) {
+        return $appid*1000000 - $avid;
+    }
+    return $avid;
+}
 
-function show_result($r) {
-    $hav = BoincHostAppVersion::lookup($r->hostid, $r->app_version_id);
+function show_result($r, $w) {
+    $gavid = gavid($r->app_version_id, $w->appid);
+    $hav = BoincHostAppVersion::lookup($r->hostid, $gavid);
     $av = BoincAppVersion::lookup_id($r->app_version_id);
     $raw_credit = $r->elapsed_time*$r->flops_estimate*COBB_SCALE;
     echo "<hr><pre>
@@ -62,7 +69,7 @@ function handle_result($resultid) {
     $rs = BoincResult::enum("workunitid=$r->workunitid and validate_state=1");
     $app_version_ids = array();
     foreach ($rs as $r) {
-        show_result($r);
+        show_result($r, $w);
         $app_version_ids[] = $r->app_version_id;
     }
     $app_version_ids = array_unique($app_version_ids);
diff --git a/lib/gui_rpc_client_ops.cpp b/lib/gui_rpc_client_ops.cpp
index 80be19c49d..13f6942b80 100644
--- a/lib/gui_rpc_client_ops.cpp
+++ b/lib/gui_rpc_client_ops.cpp
@@ -1927,14 +1927,21 @@ int RPC_CLIENT::result_op(RESULT& result, const char* op) {
 
 int RPC_CLIENT::get_host_info(HOST_INFO& h) {
     int retval;
+    char buf[256];
     SET_LOCALE sl;
     RPC rpc(this);
 
     retval = rpc.do_rpc("<get_host_info/>");
-    if (!retval) {
-        retval = h.parse(rpc.fin);
+    if (retval) return retval;
+    while (rpc.fin.fgets(buf, 256)) {
+        if (match_tag(buf, "<host_info>")) {
+            return h.parse(rpc.fin);
+        }
+        if (match_tag(buf, "<unauthorized")) {
+            return ERR_AUTHENTICATOR;
+        }
     }
-    return retval;
+    return ERR_XML_PARSE;
 }