Authentication problems with check_by_ssh

Hello everyone,

I am having problems checking remote services (file systems, users, load,
.....) using check_by_ssh.  Error received in Netsaint is "Host key
verification failed."
I run the command ( check_by_ssh -H <remote host> -l netsaint -C < command
on remote machine> ) from command line as the netsaint user and the command
executes they way it should.  Just for fun, I scheduled a cron job using
netsaint's crontab and the job executed the way it should have.  
It seems as if in my environment the Netsaint engine cannot execute plugins
that use ssh.  
I have also written some plugins that can use either ssh or rsh.  When using
rsh the plugins work great.  When using ssh through the Netsaint engine,
same type of authentication problems occur as with check_by_ssh.  When I
execute the plugins from command line or cron, they return the results as
expected.
I have generated pub/priv keys and have created the authorized_keys file on
the remote systems as expected.  All testing from command line works fine.
I am running Netsaint 0.0.7 on Redhat Linux 7.2. Netsaint process's are all
owned by the netsaint user who is part of the netsaint group.  Netsaint is
started with the standard netsaint script -> /etc/init.d/netsaint.  Ssh
version: 3.4p1  Remote ssh version's: 2.92 & 3.4p1
Can anyone help?
-john w