by Bret Miller.
OK, so we might be getting past my expertise here. Moodle does have an mnet_host table. The standard moodle table prefix would be mdl_, so normally the table would be called mdl_mnet_host. That it is looking for truemnet_host would tell me that your config.php has $CFG-prefix='true' instead of $CFG-prefx='mdl_'. Is that the case?
If so, I'm not at all sure what you do about a missing mdl_mnet_host table. I'm hoping someone else on here does...
If not, maybe there's a bug in the current 1.9.19+ that is causing the upgrade issue. It's been a long time since I've been on 1.9... That the prefix being used is "true" makes me think a variable got used the wrong way somewhere in the code.