@Gostevo,
Now I know what you ask for about. Right now I have same problem, that my Optimus Black cannot send or even download picture message (or MMS, or Multimedia message). Everytime I receive MMS, then I click "download" button, but always shows "Currently unable to download message. Please try again later". It so strange that I have not changed the settings, and some days ago I still can send and receive MMS. All 3G and data are on, but I still cannot download and send MMS. What a pity. Is there anybody (especially LG-ers) in the world know the solution?