set prompt error under csh

[Alex]

Hi,

i found a vary strange behaviour!

When i am logged in, i can set a new prompt (under csh):
set prompt "%n@%M %~ %# "
Everything alright.

But if I write the same in my .cshrc file I receive following error:
"Command must begin with a character" (or something similiar - I try to
translate from german to english ;-))
I write this command in the freebsd standard .cshrc file directly over
the "set filec" command.

What is wrong? Someone got an idea?
Thanks for your help!

Alex