ModDevTools is a few years old. Possibly its package is not kosher in the current version of MODX.
I have it installed on several versions of modx up to 2.5.7. I posted the console output to help others identify the issue. My belief is there are permission issues.
It looks like it might be a character set issue.
Can you check the character set of the modx_transport_packages table and its text fields in PhpMyAdmin against the character set in core/config/config.inc.php?
Don't thank me until it works.