Hello Rebex community,
many thanks for your help. I did not expect this.
As far as OpenNetCF.dll is concerned, there are problems in the Dial function in which calling RasSetEntryProperties + RasDial (called from coredll.dll) does not work.
A connection node is created and tries to connect to the server but the connection fails and sets a strange error in the operating system so that you can not establish a new connection to the server. Only a restart of the system resets the error.