Sorry if I'm being blind, but it looks like you're installing the Jave
Runtime Environment (JRE), not the Java Development Kit (JDK).  Can you
expect to run Netbeans w/o the JDK?

mas

Make sure you set the path to the jdk so that Netbeans can find it.

I took this from the Sun site -
http://java.sun.com/j2se/1.4.2/install-windows.html

5. Update the PATH variable (Optional)

You can run the Java 2 SDK without setting the PATH variable, or you
can optionally set it as a convenience.
Should I set the PATH variable?
Set the PATH variable if you want to be able to conveniently run the
Java 2 SDK executables (javac.exe, java.exe, javadoc.exe, etc.) from
any directory without having to type the full path of the command. If
you don't set the PATH variable, you need to specify the full path to
the executable every time you run it, such as:

   C:> \j2sdk1.4.2_<version>\bin\javac MyClass.java

It's useful to set the PATH permanently so it will persist after
rebooting.
How do I set the PATH permanently?
To set the PATH permanently, add the full path of the
j2sdk1.4.2_<version>\bin directory to the PATH variable. Typically this
full path looks something like C:\j2sdk1.4.2_<version>\bin. Set the
PATH as follows, according to whether you are on Microsoft Windows NT
or 98/2000/ME.

Microsoft Windows NT, 2000, and XP - To set the PATH permanently:

Choose Start, Settings, Control Panel, and double-click System. On
Microsoft Windows NT, select the Environment tab; on Microsoft Windows
2000 select the Advanced tab and then Environment Variables. Look for
"Path" in the User Variables and System Variables. If you're not sure
where to add the path, add it to the right end of the "Path" in the
User Variables. A typical value for PATH is:
    C:\j2sdk1.4.2_<version>\bin

Capitalization doesn't matter. Click "Set", "OK" or "Apply".
The PATH can be a series of directories separated by semi-colons (;).
Microsoft Windows looks for programs in the PATH directories in order,
from left to right. You should only have one bin directory for a Java
SDK in the path at a time (those following the first are ignored), so
if one is already present, you can update it to
j2sdk1.4.2_<version>\bin.

The new path takes effect in each new Command Prompt window you open
after setting the PATH variable.
Microsoft Windows 98 - To set the PATH permanently, open the
AUTOEXEC.BAT file and add or change the PATH statement as follows:

Start the system editor. Choose "Start", "Run" and enter sysedit, then
click OK. The system editor starts up with several windows showing. Go
to the window that is displaying AUTOEXEC.BAT

Look for the PATH statement. (If you don't have one, add one.) If
you're not sure where to add the path, add it to the right end of the
PATH. For example, in the following PATH statement, we have added the
bin directory at the right end:

PATH C:\WINDOWS;C:\WINDOWS\COMMAND;C:\J2SDK1.4.2_<version>\BIN

Capitalization doesn't matter. The PATH can be a series of directories
separated by semi-colons (;). Microsoft Windows searches for programs
in the PATH directories in order, from left to right. You should only
have one bin directory for a Java SDK in the path at a time (those
following the first are ignored), so if one is already present, you can
update it to j2sdk1.4.2_<version>.

To make the path take effect in the current Command Prompt window,
execute the following:
     C:> c:\autoexec.bat

To find out the current value of your PATH, to see if it took effect,
at the command prompt, type:
     C:> path

Microsoft Windows ME - To set the PATH permanently:

system information. This brings up a window titled "Microsoft Help and
Support". From here, choose the tools menu, then select the system
configuration utility. Click the environment tab, select PATH and press
the edit button. Now add the SDK to your path as described in step b
above. After you've added the location of the SDK to your PATH, save
the changes and reboot your machine when prompted.