NoClassDefFoundError and Checking for updates failed


when trying to update the jme3 sdk (via help->check for updates) I get the following error message:

“Check your network connection, verify that your proxy settings are configured correctly, or try again later.”

Regularly I get the following error (In the bottom right corner, where the sdk also informs about updates):

java.lang.NoClassDefFoundError: org/netbeans/updater/XMLUtil
at org.netbeans.modules.autoupdate.updateprovider.AutoupdateCatalogParser.newEntityResolver(
at org.netbeans.modules.autoupdate.updateprovider.AutoupdateCatalogParser.(
at org.netbeans.modules.autoupdate.updateprovider.AutoupdateCatalogParser.getUpdateItems(
at org.netbeans.modules.autoupdate.updateprovider.AutoupdateCatalogProvider.getUpdateItems(
at org.netbeans.modules.autoupdate.updateprovider.AutoupdateCatalogProvider.getContentDescription(
at org.netbeans.api.autoupdate.UpdateUnitProvider.getContentDescription(
at org.netbeans.modules.autoupdate.ui.actions.CheckForUpdatesProviderImpl.getContentDescription(
at org.netbeans.core.ui.ProductInformationPanel.getUpdates(
at org.netbeans.core.ui.ProductInformationPanel.access$000(
at org.netbeans.core.ui.ProductInformationPanel$
at org.openide.util.RequestProcessor$
[catch] at org.openide.util.RequestProcessor$

My network connection works just fine! I’m using SDK 3.0RC2 and “1.7.0_17; Java HotSpot™ 64-Bit Server VM 23.7-b01” is installed.
My System: Windows 7 version 6.1 running on amd64; Cp1252; en_US
Reinstallation leaded to working updates at first. After the usual restart of the sdk after an update, the error and the update failure reappeared.


is that the latest java 7? I had issue with downloading updates as well with Java 7, but this was like 6 months ago or something