I found the problem:
I checked everything again using the tool pexports, and both sqlite3-core.dll and sqlite3.dll were exporting all symbols. I compare all with the following article:
The only thing left to do was to put sqlite.dll in the emacs\bin folder and Voilà, now it works. In fact I had already added the path and used to sqlite3.dll in my emacs init file, but the location was wrong; after my emacs-modules collection.
Thank you for your feedback and support.
Muchas gracias Oscar Fuentes por tu colaboración.