enhanced debugging

source/net/yacy/cora/protocol/TimeoutRequest.java

@@ -279,7 +279,7 @@ public class TimeoutRequest<E> {
                 } }
             }).call(timeout).longValue();
         } catch (final ExecutionException e) {
-            throw new IOException(e.getMessage());
+            throw new IOException(file.toString() + ":" + e.getMessage());
         }
     }
 

source/net/yacy/crawler/HostBalancer.java

@@ -348,6 +348,8 @@ public class HostBalancer implements Balancer {
             return request;
         } catch (ConcurrentModificationException e) {
             continue tryagain;
+        } catch (IOException e) {
+            throw e;
         } catch (Throwable e) {
             throw new IOException(e.getMessage());
         }