TERM environment variable not set

You've answered the question with this statement:

Cron calls this .sh every 2 minutes

Cron does not run in a terminal, so why would you expect one to be set?

The most common reason for getting this error message is because the script attempts to source the user's .profile which does not check that it's running in a terminal before doing something tty related. Workarounds include using a shebang line like:

#!/bin/bash -p

Which causes the sourcing of system-level profile scripts which (one hopes) does not attempt to do anything too silly and will have guards around code that depends on being run from a terminal.

If this is the entirety of the script, then the TERM error is coming from something other than the plain content of the script.

Using a terminal command i.e. "clear", in a script called from cron (no terminal) will trigger this error message. In your particular script, the smbmount command expects a terminal in which case the work-arounds above are appropriate.

You can see if it's really not set. Run the command set | grep TERM.

If not, you can set it like that: export TERM=xterm