I tried updating using
http://dl.google.com/eclipse/inst/d2gwt/beta/3.6 and got the following error:
An error occurred while collecting items to be installed
session context was:(profile=epp.package.jee, phase=org.eclipse.equinox.internal.p2.engine.phases.Collect, operand=, action=).
No repository found containing: osgi.bundle,com.google.gdt.eclipse.designer,2.2.0.r36x201103071541
No repository found containing: osgi.bundle,com.google.gdt.eclipse.designer.GWTExt,2.2.0.r36x201103071544
No repository found containing: osgi.bundle,com.google.gdt.eclipse.designer.GXT,2.2.0.r36x201103071544
No repository found containing: osgi.bundle,com.google.gdt.eclipse.designer.GXT.databinding,2.2.0.r36x201103071544
No repository found containing: osgi.bundle,com.google.gdt.eclipse.designer.SmartGWT,2.2.0.r36x201103071544
No repository found containing: osgi.bundle,com.google.gdt.eclipse.designer.UiBinder,2.2.0.r36x201103071541
No repository found containing: osgi.bundle,com.google.gdt.eclipse.designer.UiBinder.wizards,2.2.0.r36x201103071544
No repository found containing: osgi.bundle,com.google.gdt.eclipse.designer.doc.user,2.2.0.r36x201103071544
No repository found containing: org.eclipse.update.feature,com.google.gdt.eclipse.designer.editor.feature,2.2.0.r36x201103071541
No repository found containing: org.eclipse.update.feature,com.google.gdt.eclipse.designer.feature,2.2.0.r36x201103071544
No repository found containing: osgi.bundle,com.google.gdt.eclipse.designer.hosted,2.2.0.r36x201103071218
No repository found containing: osgi.bundle,com.google.gdt.eclipse.designer.hosted.1_6,2.2.0.r36x201103071218
No repository found containing: osgi.bundle,com.google.gdt.eclipse.designer.hosted.1_6.super,2.2.0.r36x201103071218
No repository found containing: osgi.bundle,com.google.gdt.eclipse.designer.hosted.2_0,2.2.0.r36x201103071218
No repository found containing: osgi.bundle,com.google.gdt.eclipse.designer.hosted.2_0.super,2.2.0.r36x201103071218
No repository found containing: osgi.bundle,com.google.gdt.eclipse.designer.hosted.2_0.webkit,2.2.0.r36x201103071218
No repository found containing: osgi.bundle,com.google.gdt.eclipse.designer.hosted.2_0.webkit_win32x64,2.2.0.r36x201103071218
No repository found containing: osgi.bundle,com.google.gdt.eclipse.designer.hosted.2_2,2.2.0.r36x201103071218
No repository found containing: osgi.bundle,com.google.gdt.eclipse.designer.hosted.2_2.webkit,2.2.0.r36x201103071218
No repository found containing: org.eclipse.update.feature,com.google.gdt.eclipse.designer.hosted.feature,2.2.0.r36x201103071218
No repository found containing: osgi.bundle,com.google.gdt.eclipse.designer.hosted.lib,2.2.0.r36x201103071218
No repository found containing: osgi.bundle,com.google.gdt.eclipse.designer.launch,2.2.0.r36x201103071544
No repository found containing: osgi.bundle,com.google.gdt.eclipse.designer.preferences,2.2.0.r36x201103071544
No repository found containing: osgi.bundle,com.google.gdt.eclipse.designer.usageprofiler,2.2.0.r36x201103071544
No repository found containing: osgi.bundle,com.google.gdt.eclipse.designer.usageprofiler.ui,2.2.0.r36x201103071544
No repository found containing: osgi.bundle,com.google.gdt.eclipse.designer.wizards,2.2.0.r36x201103071544
No repository found containing: osgi.bundle,org.eclipse.wb.core,0.9.0.r36x201103071212
No repository found containing: osgi.bundle,org.eclipse.wb.core.databinding,0.9.0.r36x201103071212
No repository found containing: osgi.bundle,org.eclipse.wb.core.databinding.xml,0.9.0.r36x201103071215
No repository found containing: org.eclipse.update.feature,org.eclipse.wb.core.feature,0.9.0.r36x201103071212
No repository found containing: osgi.bundle,org.eclipse.wb.core.lib,0.9.0.r36x201103071212
No repository found containing: osgi.bundle,org.eclipse.wb.core.ui,0.9.0.r36x201103071215
No repository found containing: org.eclipse.update.feature,org.eclipse.wb.core.ui.feature,0.9.0.r36x201103071215
No repository found containing: osgi.bundle,org.eclipse.wb.core.xml,0.9.0.r36x201103071215
No repository found containing: org.eclipse.update.feature,org.eclipse.wb.core.xml.feature,0.9.0.r36x201103071215
No repository found containing: osgi.bundle,org.eclipse.wb.css,0.9.0.r36x201102190706
No repository found containing: org.eclipse.update.feature,org.eclipse.wb.css.feature,0.9.0.r36x201102190706
No repository found containing: osgi.bundle,org.eclipse.wb.doc.user,0.9.0.r36x201103071214
No repository found containing: org.eclipse.update.feature,org.eclipse.wb.doc.user.feature,0.9.0.r36x201103071214
No repository found containing: osgi.bundle,org.eclipse.wb.jdt.fragment,0.9.0.r36x201103071212
No repository found containing: osgi.bundle,org.eclipse.wb.os,0.9.0.r36x201103071212
No repository found containing: osgi.bundle,org.eclipse.wb.os.win32,0.9.0.r36x201103071212
No repository found containing: osgi.bundle,org.eclipse.wb.runtime,0.9.0.r36x201103071212
No repository found containing: osgi.bundle,org.eclipse.wb.runtime.lib,0.9.0.r36x201103071212
I am running on a 64-bit computer using the 64-bit JDK...I will try it with 32-bit.