So I was getting the "unable to start activity...java.lang.nullPointerException" error and took plusminus' advice. I first added -wipe-data under "Additional Emulator Command Line Options but that didn't work. I then went ahead and deleted userdata.img and when I run my app I get this under the Console:

[2008-02-27 11:49:13 - Actividad] ------------------------------
[2008-02-27 11:49:13 - Actividad] Android Launch!
[2008-02-27 11:49:13 - Actividad] adb is running normally.
[2008-02-27 11:49:13 - Actividad] Launching: com.test.actividad.Page1
[2008-02-27 11:49:13 - Actividad] Automatic Target Mode: launch emulator.
[2008-02-27 11:49:13 - Actividad] Launching a new emulator.

...but the emulator never shows up!

Heeelp.

Hello malatorre,

if the file is missing (i.e. right after your very first installation of android) the android sdk should generate that file. Also when you delete it.
(Tested with vista)

The log looks just fine. Maybe also delete the other files you find in there.

Regards,
plusminus