error LD: undefined variable while changing shell from bash to csh

Hi,
i am a beginner in ubuntu. my default shell is bash. everytime i try to change the shell with command "csh", i get a message (probably an error message). after i get into c-shell, when i try to execute a c shellscript, then it showed the same message. any idea about what is this about or any links which will help me learn more about this stuff ?

avinash@ubuntu:~$ csh
LD: Undefined variable.
%

Thanks.

Regards,
Avinash

Sounds like linking problems.

whereis csh

then

ldd /path/to/csh