And i have not the faintest idea why

I run Oracle on HPUX and today found out the following:

Machine 1 (the one where the database is running)

I have a listener startet (lsnrctl status -> gives normal information)
tnsping works: tnsping
-> I can see the right ip adress and port in the console.

Machine 2
tnsping does not work
-> i can see the right ip adress and port in the console when tnsping uses the tnsnames.ora
but i get: TNS-12541: TNS:no listener

has anyone an idea where i could find a solution?
I change even the port (thought of conflicts) but with no success...

so long
Torgum