setenv is a C shell command, but you're running bash which has no such command.
There are two major families of unix shells: the Bourne family and the C family. Bash, the default shell on most Linux systems, is a member of the Bourne family (“bash” stands for “Bourne-again shell”). The C family has fallen into disuse, its features have now mostly been imitated and improved in bash and zsh.
You've clearly inserted some C shell instructions into one of your shell startup files (
.bashrc, perhaps?). You'll need to undo that.
If you have C shell instructions and you need help translating them into Bourne syntax, feel free to ask here. The most important thing to know is that to set an environment variable in the C shell, you write
setenv VARIABLE_NAME "some value"
In a Bourne shell, you write this in
~/.profile (or in
/etc/profile if it's for all users):
export VARIABLE_NAME="some value"