My problem is that I want to translate LedgerSMB to Spanish Venezuela, I know that already it is, but there are still some words that are not. So I'm trying to add them.
There's a section dedicated to translation. That should help you to get started.
The basic idea is that everything you can learn from the web about translating with gettext applies to LedgerSMB's gettext translation as well, with the note that you should be able to find a recent POT file in the repository next to the source code for the latest development version (trunk) and the latest stable release (1.3).