Comment 1 for bug 390265

Oh yes, this method was introduced in Qt 4.4: You're probably using 4.3. I'm commiting a fix to svn but you can easily apply the fix yourself in order to compile quickly:

--- src/searchEngine.cpp (revision 2331)
+++ src/searchEngine.cpp (working copy)
@@ -269,7 +269,7 @@
     }
   }
   qDebug("Deleting downloadProcess");
- downloaders.removeOne(downloadProcess);
+ downloaders.removeAll(downloadProcess);
   delete downloadProcess;
 }