I’m very happy to report that NetBeans developers have unrolled the changes that broke the Substance NetBeans module (reported in early May on NetBeans bug tracker). And so, if you’re using the daily builds of NetBeans 6.0 (after July 26th), you can install the latest development drop of Substance 4.0 module (code-named Key Largo).
Many thanks to NetBeans team and Standa Aubrecht in particular for listening to the community and making these changes that allow third-party look-and-feels to provide modules for both NetBeans IDE itself and NetBeans RCP programs. Standa was courteous enough to provide a patch that removes usage of deprecated APIs and unnecessary functionality. The only minor defect that will be fixed in the consistent appearance for tab scroll buttons.