I am running Apache Cordova 3.6.3-0.2.13. And I try to get the splash screens working. I have followed the documentation on http://cordova.apache.org/docs/en/3.6.0/config_re
I had a similar issue on android, I put the Splash Screen Directly into res/drawable-hdpi and got the following error during cordova build.
res/drawable-hdpi-v4/DocBackground.png: Invalid file name: must contain only [a-z0-9_.]
When I de-capitalised the file name, in ~project/icons, cordova build copied them to the res/drawable folder & splash screen worked.