See http://www.netbeans.org/issues/show_bug.cgi?id=132941

java.lang.IllegalArgumentException: "null" expected to be an integer
at com.sun.servicetag.Util.getIntValue(Util.java:66)
at com.sun.servicetag.Registry.parseServiceTag(Registry.java:460)
at com.sun.servicetag.Registry.getServiceTag(Registry.java:424)
at org.netbeans.modules.reglib.NbServiceTagSupport.installSystemServiceTag(NbServiceTagSupport.java:639)
at org.netbeans.modules.reglib.NbServiceTagSupport.createNbServiceTag(NbServiceTagSupport.java:194)
at org.netbeans.modules.registration.NbInstaller.restored(NbInstaller.java:98)
at org.netbeans.core.startup.NbInstaller.loadCode(NbInstaller.java:378)
[catch] at org.netbeans.core.startup.NbInstaller.load(NbInstaller.java:297)

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As far as I understand, Tumbleweed has STClient.exe installed (probably) at
C:\Program Files\Tumbleweed\STClient\STClient.exe

Sun`s client is usualy installed at
C:\Program Files\Sun\servicetag\stclient.exe

The stclient.exe (whatever installed) is also "registered" it at HKLM\software\microsoft\windows\currentversion\app
paths\stclient.exe on the first execution (if I am not mistaken)

The JDK`s ServiceTag implementation reads this registry key (Util.getWindowsStClientFile()) and uses Tumbleweed`s
stclient for the servicetag purposes. That is likely wrong...