Did you check the Status of the records in CTM:LoadPostalCodes? Do you see any records in Validated state?
As said, loading Geography through DMT was just a test. I'm having many problems using DMT. I'll try to explain later, I think better in a new thread.
As DMT 8.0 documentation explains:
Exclusions from data load
The following foundation forms are excluded from bulk load data management:
- CFG:Geography City
- CFG:Geography Country
- CFG:Geography Stat/Province
These foundation geography forms are excluded because BMC Remedy ITSM provides extensive data for all these forms with installation of the applications. To import additional data, import the records directly into these forms using BMC Remedy Data Import. For information about using BMC Remedy Data Import, see the BMC Remedy Data Import help.
i.e. you cannot load cities using DMT. In fact, Geography.xls should be used only to load zip codes related to "existing" cities.