After fvwm2-installing twm fails
 

Hallo,
I am on a Win98/cygwin environment, so I hope this forum is still of help.
I run xfree86 and bundeled the startx with ssh tunneling (kerberos). Starting x with startx just bring up the x session with the twm term and working well. I upgraded (well, I installed some proggies like fvwm, opengl,....) the cygwin with the setup.exe installer. After reboot the startx shows first the same behavior as before, but closes the x session, whilst doing further loading of twm in bash, which ends up with closing down the whole session, indicating the session was killed and "signal 15".
The fvwm2 does work, but not properly. It is displayed one term window, which I can resize, that's all. No popup menu, no mouse menu.
Actually I'd prefer the twm.
Any ideas?
Juergen