Denon Binding: No input data from the AV-Receiver within openhab

I have an issue where the binding is not starting correctly. I can send commands to the receiver (X1200W) but do not receive anything from it. All these http URLs deliver data when putting them in the browser:
http://192.168.1.70/goform/formMainZone_MainZoneXml.xml
http://192.168.1.70/goform/formMainZone_MainZoneXmlStatus.xml
http://192.168.1.70/goform/formZone2_Zone2XmlStatusLite.xml
http://192.168.1.70/goform/formZone3_Zone3XmlStatusLite.xml
http://192.168.1.70/goform/formZone3_Zone4XmlStatusLite.xml
http://192.168.1.70/goform/Deviceinfo.xml
http://192.168.1.70/goform/AppCommand.xml
http://192.168.1.70/goform/formiPhoneAppDirect.xml

When I remove the file org.openhab.binding.denon-1.7.1.jar in my addons folder and put it back in again the binding seems to start. From this point I receive data from the receiver within openhab. I am using OH 1 runtime.

Can somebody help me?

I get these errors:

2015-12-06 15:11:03.988 [ERROR] [g.openhab.io.net.http.HttpUtil] - Fatal transport error: java.net.SocketTimeoutException: Read timed out
2015-12-06 15:11:04.000 [ERROR] [.service.AbstractActiveService] - Error while executing background thread Denon Refresh Service
java.lang.NullPointerException: null
at org.apache.commons.io.IOUtils.toInputStream(IOUtils.java:769) ~[na:na]
at org.openhab.binding.denon.internal.DenonConnector.getDocument(DenonConnector.java:545) ~[na:na]
at org.openhab.binding.denon.internal.DenonConnector.updateMain(DenonConnector.java:421) ~[na:na]
at org.openhab.binding.denon.internal.DenonConnector.refreshHttpProperties(DenonConnector.java:493) ~[na:na]
at org.openhab.binding.denon.internal.DenonConnector.updateState(DenonConnector.java:199) ~[na:na]
at org.openhab.binding.denon.internal.DenonBinding.execute(DenonBinding.java:71) ~[na:na]
at org.openhab.core.binding.AbstractActiveBinding$BindingActiveService.execute(AbstractActiveBinding.java:156) ~[na:na]
at org.openhab.core.service.AbstractActiveService$RefreshThread.run(AbstractActiveService.java:173) ~[na:na]
2015-12-06 15:11:13.008 [ERROR] [g.openhab.io.net.http.HttpUtil] - Fatal transport error: java.net.SocketTimeoutException: Read timed out
2015-12-06 15:11:13.015 [ERROR] [.service.AbstractActiveService] - Error while executing background thread Denon Refresh Service
java.lang.NullPointerException: null
at org.apache.commons.io.IOUtils.toInputStream(IOUtils.java:769) ~[na:na]
at org.openhab.binding.denon.internal.DenonConnector.getDocument(DenonConnector.java:545) ~[na:na]
at org.openhab.binding.denon.internal.DenonConnector.updateMain(DenonConnector.java:421) ~[na:na]
at org.openhab.binding.denon.internal.DenonConnector.refreshHttpProperties(DenonConnector.java:493) ~[na:na]
at org.openhab.binding.denon.internal.DenonConnector.updateState(DenonConnector.java:199) ~[na:na]
at org.openhab.binding.denon.internal.DenonBinding.execute(DenonBinding.java:71) ~[na:na]
at org.openhab.core.binding.AbstractActiveBinding$BindingActiveService.execute(AbstractActiveBinding.java:156) ~[na:na]
at org.openhab.core.service.AbstractActiveService$RefreshThread.run(AbstractActiveService.java:173) ~[na:na]
2015-12-06 15:11:20.250 [WARN ] [.denon.internal.DenonConnector] - Error sending command
java.util.concurrent.TimeoutException: Request timeout of 5000 ms
at com.ning.http.client.providers.netty.timeout.TimeoutTimerTask.expire(TimeoutTimerTask.java:43) [async-http-client-1.8.4.jar:na]
at com.ning.http.client.providers.netty.timeout.RequestTimeoutTimerTask.run(RequestTimeoutTimerTask.java:41) [async-http-client-1.8.4.jar:na]
at org.jboss.netty.util.HashedWheelTimer$HashedWheelTimeout.expire(HashedWheelTimer.java:546) [netty-3.9.0.Final.jar:na]
at org.jboss.netty.util.HashedWheelTimer$Worker.notifyExpiredTimeouts(HashedWheelTimer.java:446) [netty-3.9.0.Final.jar:na]
at org.jboss.netty.util.HashedWheelTimer$Worker.run(HashedWheelTimer.java:395) [netty-3.9.0.Final.jar:na]
at org.jboss.netty.util.ThreadRenamingRunnable.run(ThreadRenamingRunnable.java:108) [netty-3.9.0.Final.jar:na]
at java.lang.Thread.run(Thread.java:745) [na:1.7.0_60]
2015-12-06 15:11:22.022 [ERROR] [g.openhab.io.net.http.HttpUtil] - Fatal transport error: java.net.SocketTimeoutException: Read timed out
2015-12-06 15:11:22.030 [ERROR] [.service.AbstractActiveService] - Error while executing background thread Denon Refresh Service
java.lang.NullPointerException: null
at org.apache.commons.io.IOUtils.toInputStream(IOUtils.java:769) ~[na:na]
at org.openhab.binding.denon.internal.DenonConnector.getDocument(DenonConnector.java:545) ~[na:na]
at org.openhab.binding.denon.internal.DenonConnector.updateMain(DenonConnector.java:421) ~[na:na]
at org.openhab.binding.denon.internal.DenonConnector.refreshHttpProperties(DenonConnector.java:493) ~[na:na]
at org.openhab.binding.denon.internal.DenonConnector.updateState(DenonConnector.java:199) ~[na:na]
at org.openhab.binding.denon.internal.DenonBinding.execute(DenonBinding.java:71) ~[na:na]
at org.openhab.core.binding.AbstractActiveBinding$BindingActiveService.execute(AbstractActiveBinding.java:156) ~[na:na]
at org.openhab.core.service.AbstractActiveService$RefreshThread.run(AbstractActiveService.java:173) ~[na:na]

Errors fixed with 1.8 snapshot. Thanks.