SORRY, My bad.
MY phone was very low on memory. Once I cleared up some space by removing a big game file, I now have more room, and the app is updating the collection.

I get the "The remote server returned an error: NotFound." too.

There isn't any firewall running, I tried different ports (although there is no web server running and the ports are unused), my security software is disabled/shut down.
The ip address used in the wp app is the one of my computer running DVD Profiler and Restifier.

Is there any way to transfer the "collection.xml" to my windows phone and import it in "DVD Register"?

Fat chance of that happening. It's been 4 years since people asked so isn't
Likely to happen.

Can anyone verify that this is working with DVDP 3.9.0 & WP 8.1?

Thanks.

I cannot get mine to sync. Server, directory and port number match in both places.

I get the following error in the Restifier logfile:

192.168.0.14 500 http://192.168.0.11:2080/DvdProfilerService/ProfileIdList?ETags=Profile,FrontCover,BackCover&nocache=1 0.045s
System.InvalidCastException: Unable to cast COM object of type 'System.__ComObject' to interface type 'Invelos.DVDProfilerPlugin.IDVDProfilerAPI'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{8AFA0FCD-91B4-47F5-8663-CF72CA05B360}' failed due to the following error: Element not found. (Exception from HRESULT: 0x8002802B (TYPE_E_ELEMENTNOTFOUND)).
  at Invelos.DVDProfilerPlugin.IDVDProfilerAPI.GetDVDProfilerVersion()
  at Bevelstone.DvdProfiler.Module.Restify.Plugin.RequestHandler..ctor(IDVDProfilerAPI dvdProfilerApi, HttpListenerContext context)

DVD register seems to be gone in de Windows 10 Mobile Store. Its running smooth on my 950XL but recently I did buy my self a HP elite X3 and the app is missing in the store!
Is there anyway to get the app back or have at least some kind of a workaround, which is not droid or ios.

A long time ago I started writing a plugin that would keep an export synchronized on OneDrive, allowing DVD Register to sync without the Restifier hell. But then I asked myself one simple question: Why am I using a program that does not provide easy access to the data? That was the last time I opened DVD Profiler.

Unfortunately at the time Microsoft required age ratings to be updated in the store I was suffering from a burn-out, so I was unable to follow up when supplying the requested data failed. So now the application is delisted and bringing it back would require a new certification - which means upgrading it.

I just tried sideloading the XAP file I have (the one Cineast links to) on a Lumia 950 XL using the Windows 8 SDK. It failed with an error code. I then tried loading the source code into Visual Studio 2015 and it updates it to a Windows Phone 8 project... which does not compile due to conflicts in class names between the toolkit used for 7.x phone development and the 8.x classes. I spend 5 minutes trying to fix it and failed.

So I am afraid that this is it from my side. DVD Profiler just isn't useful for me without data access and I am busy with many other (more important and/or fun and/or interesting) projects - so I can't free up any time for this.

If someone else wants the source code to try to get it running please let me know.