The first screen in the wizard is blank or empty, only shows me Cancel button. I'm Working in UBUNTU 12.04 I reinstalled Netbeans and the problem is still there, I tried with NB 7.1.1 and NB 7.1.2 I'm using Oracle JDK 7 http://netbeans-org.1045718.n5.nabble.com/file/n5684540/38.png
Weird! That might be related to memory usage, a broken JDK installation a broken LAF (Nimbus or GTK+)..Can't tell. Please provide more details. Netbeans 7.1.x works perfectly under 12.04. When Netbeans is started, click on the red icon on right bottom. This will reveal a dialog with details about eventual startup errors. and paste it in your question.
Meanwhile can you start your netbeans using this command and tell us what the result is:
I'll update my answer dependently on your feedback.