Nice that you found the problem. To summarize the installation of NetBeans IDE in case anyone else have problems with it.
1.
Install a Java Development Kit
2. Make the NetBeans installer executable
3. Launch the NetBeans installer as root and complete the installation
4. Create a symlink in /usr/local/bin that points to e.g. /opt/netbeans-5.0beta/bin/netbeans depending of course exactly where one installed NetBeans.
5. Install any other NetBeans modules, e.g. the mobility kit. Don't forget to make sure their installers are executable too