to run a remote program using ssh; path problem(?) should be easy, but not

Hya,

Set up Three penguin (Debian amd64) cluster (slurm); All share one nfs drive, Two of them are headless. There is a directory on nfs where executables are stored. All penguins are happy.

Touble When I tried a remote program on nfs drive by ssh, something I do not understand happened. From Headed penguin to headless1:Code:>ssh -Y user@headless1 remote_prg
>remote_prg: Command not found. (Why? ...)
>ssh -Y user@headless1 /path/to/nfs/prog/remote_prg
(works)
..
>ssh -Y user@headless1 echo $path
/path/to/nfs/prog .... (whatever as expected)Another problem I do not understand is that from headed to headless2:Code:>ssh -Y user@headless2 remote_prg
(works)What I thought 1. headless1 cannot locate exectable. 2. path to exectable is ok (reason, echo $path) 3. exectable flag on nfs drive is ok (reason, full path works) 4. ssh/sshd configs are irrelevant. (reason, same as 3) 5. As setup is by tcsh, .tcshrc and .login are checked, but no clue.

Question Can any expert direct me to next step?

Thanks in advance.
cheers