Hello Koen,
it seems that TOPCAT is correctly connected with WideFS and Flightsim is correctly connected with FSUIPC.
But there seems to be a connection problem between FSUIPC and WideFS.
As guitaman already wrote: if you switch Flightsim to window mode (non-fullscreen -> ALT+Enter) you shjould see either 'waiting for connection' or '1 connection'. If it says - what I assume - 'waiting for connection' there is a problem between FSUIPC and WideFS. That's a job for Pete Dowson from FSUIPC. Take a look at http://www.schiratti.com/dowson.html

