rexec in ISC, GNU tar fails

[fritz zaucker]

I have a problem running GNU tar over a remote connection.
I have tar-1.08 and want to access a tape on a remote host (TCPIP).

I am running Interactive Unix ver. 2.02 (SysV3.2). Therefore I compiled
withe USE_REXEC. To use tar I made a correct ~/.netrc file (ftp works
and doesn't ask for password or login).
When using GNU-tar with:
tar -tf host:/dev/tape the login is rejected with the message
Login incorrect
According to the rexecd(1m) man page this means 
No password file entry for the user name existed.

Something is wrong. Any hints?

Thanks

Fritz