diff --git a/html/inc/submit_db.inc b/html/inc/submit_db.inc
index 61c6e6b84b..9c5a0f66e2 100644
--- a/html/inc/submit_db.inc
+++ b/html/inc/submit_db.inc
@@ -100,11 +100,11 @@ class BoincUserSubmitApp {
     }
     static function delete_user($user_id) {
         $db = BoincDb::get();
-        $db->delete_aux('user_submit_app', "user_id=$user_id");
+        return $db->delete_aux('user_submit_app', "user_id=$user_id");
     }
     function update($clause) {
         $db = BoincDb::get();
-        $db->update_aux('user_submit_app', "$clause where user_id=$this->user_id and app_id=$this->app_id");
+        return $db->update_aux('user_submit_app', "$clause where user_id=$this->user_id and app_id=$this->app_id");
     }
 }
 
@@ -121,7 +121,7 @@ class BoincJobFile {
     }
     function delete() {
         $db = BoincDb::get();
-        $db->delete($this, 'job_file');
+        return $db->delete_aux($this, 'job_file', "md5='$this->md5'");
     }
     function update($clause) {
         $db = BoincDb::get();
@@ -142,13 +142,13 @@ class BoincBatchFileAssoc {
     }
     function delete() {
         $db = BoincDb::get();
-        $db->delete_aux('batch_file_assoc',
+        return $db->delete_aux('batch_file_assoc',
             "job_file_id=$this->job_file_id and batch_id=$this->batch_id"
         );
     }
     static function delete_batch($batch_id) {
         $db = BoincDb::get();
-        $db->delete_aux('batch_file_assoc',
+        return $db->delete_aux('batch_file_assoc',
             "batch_id=$batch_id"
         );
     }
diff --git a/html/user/job_file.php b/html/user/job_file.php
index 76edd37930..a4821a20e1 100644
--- a/html/user/job_file.php
+++ b/html/user/job_file.php
@@ -116,6 +116,9 @@ function query_files($r) {
                 $jf_id = BoincJobFile::insert(
                     "(md5, create_time, delete_time) values ('$md5', $now, $delete_time)"
                 );
+                if (!$jf_id) {
+                    xml_error(-1, "query_file(): BoincJobFile::insert($md5) failed: ".BoincDb::error());
+                }
             }
             // create batch association if needed
             //
@@ -131,7 +134,12 @@ function query_files($r) {
             }
         } else {
             if ($job_file) {
-                $job_file->delete();
+                $ret = $job_file->delete();
+                if (!$ret) {
+                    xml_error(-1,
+                        "BoincJobFile::delete() failed: ".BoincDb::error()
+                    );
+                }
             }
             $absent_files[] = $i;
         }
@@ -166,7 +174,7 @@ function upload_files($r) {
             "(md5, create_time, delete_time) values ('$md5', $now, $delete_time)"
         );
         if (!$jf_id) {
-            xml_error(-1, "BoincJobFile::insert($md5) failed: ".BoincDb::error());
+            xml_error(-1, "upload_files(): BoincJobFile::insert($md5) failed: ".BoincDb::error());
         }
         if ($batch_id) {
             BoincBatchFileAssoc::insert(
diff --git a/samples/condor/boinc_gahp.cpp b/samples/condor/boinc_gahp.cpp
index f27cbc019e..eec33bdf3d 100644
--- a/samples/condor/boinc_gahp.cpp
+++ b/samples/condor/boinc_gahp.cpp
@@ -125,9 +125,11 @@ void filename_extension(const char* path, char* ext) {
 
 int compute_boinc_name(string path, LOCAL_FILE& f) {
     char md5[64], ext[256];
-    return md5_file(path.c_str(), md5, f.nbytes);
+    int retval = md5_file(path.c_str(), md5, f.nbytes);
+    if (retval) return retval;
     filename_extension(path.c_str(), ext);
     sprintf(f.boinc_name, "%s%s", md5, ext);
+    return 0;
 }
 
 const char *escape_str(const string &str) {
diff --git a/tools/remote_submit_test.cpp b/tools/remote_submit_test.cpp
index 9bf213b1a7..774985fe74 100644
--- a/tools/remote_submit_test.cpp
+++ b/tools/remote_submit_test.cpp
@@ -19,6 +19,9 @@
 
 #include "remote_submit.h"
 
+using std::vector;
+using std::string;
+
 const char* project_url = "http://isaac.ssl.berkeley.edu/test/";
 const char* authenticator = "157f96a018b0b2f2b466e2ce3c7f54db";