Error launching arduino IDE for the first time


my first arduino board (duemilanove) has just arrived… I’ve installed the drivers (I’m on windows XP SP3), connected the board, everything ok so far…

But when I launch the software (version 0018) I get this message:

"launch4j An error occurred while starting the application. Access denied"

And the program ends. I searched a fix for that problem, and I read that someone solved deleting the ‘preferences.txt’ file in C:\Documents and settings<MY_USER>\Application data\arduino\preferences.txt… But I have not that file.

What can I do?

thank you very much

EDIT: in the lib/preferences.txt file refers to another path:

Documents and Settings → [username] → Application Data →

Processing → preferences.txt (on Windows XP)

But I’m not able to find neither this path (it’s not a problem of hidden files, I have enabled the visualization of hidden and system files)