Check to see if the image has the correct name.
It should be sign_up_submit.9.png, the lines that appear are actually the areas that the 9patch defines for stretch.
If the image has the correct name it is a chance that the online utility application you used messed the resource. Try to use the 9patch generator from the android sdk(look for [your_sdk_path]\tools\draw9patch.bat), and try to generate one yourself and see if the problem is still there.