What version of MODx are you running, just 0.9.2 or 0.9.2.1? Patching your install to 0.9.2.1 will get rid of the second error. The first error can be fixed by changing the two lines starting at 685 from:
if ($msg /* $php_errormsg is not defined!!!! && $php_errormsg */
) {
to one line:
if ($msg && isset( $php_errormsg )) {
The odd thing is again, if stopOnNotice is not set to true, then these should be ignored by the MODx error handler and according to your default error_reporting level from PHP ini, everything appears to be configured properly. I’ll try and dig into this more when I get some more time.
Now from your phpinfo, I see you are running PHP 4.3.0, and though technically MODx does work on this version of PHP, the security holes and vulnerabilities in that version of PHP itself are worth upgrading. If this is a hosting provider, I honestly suggest changing to a provider that at least stays up to date with security patches for the web environment.