Can't run DS-5 in 13.1

I'm trying to upgrade to 13.1 of the EDS tools on a Win7 box.

This may have been caused by a Windows Update but I don't know. After installing the EDS the DS-5 installer started and on the second or third wizard page, a message popped up saying there was a Windows Update pending and it strongly recommended that I reboot before continuing. I rebooted, then ran the DS-5 install from the embedded/ds-5 directory and everything seemed fine. Then I open the Embedded Command Shell as usual, but when I type eclipse to launch DS-5, said DS-5 couldn't be found. At this point I probably could have played with the environment variables a bit and got it working, but instead I uninstalled everything and started over. Now when I try launching DS-5 it throws an error which points me to the error log file. The log file contains the message below.

!SESSION Fri Apr 04 13:35:50 MDT 2014 ------------------------------------------

!ENTRY org.eclipse.equinox.launcher 4 0 2014-04-04 13:35:50.283

!MESSAGE Could not find extension: reference:file:org.eclipse.osgi.nl_ja_3.7.0.v20110723043401.jar

!ENTRY org.eclipse.equinox.launcher 4 0 2014-04-04 13:35:50.285

!MESSAGE Could not find extension: reference:file:org.eclipse.osgi.services.nl_ja_3.7.0.v20110723043401.jar

!ENTRY org.eclipse.equinox.launcher 4 0 2014-04-04 13:35:50.285

!MESSAGE Could not find extension: reference:file:org.eclipse.osgi.util.nl_ja_3.7.0.v20110723043401.jar

!ENTRY org.eclipse.equinox.launcher 4 0 2014-04-04 13:35:50.321

!MESSAGE Exception launching the Eclipse Platform:

!STACK

java.lang.ClassNotFoundException: org.eclipse.core.runtime.adaptor.EclipseStarter

at java.net.URLClassLoader$1.run(URLClassLoader.java:202)

at java.security.AccessController.doPrivileged(Native Method)

at java.net.URLClassLoader.findClass(URLClassLoader.java:190)

at java.lang.ClassLoader.loadClass(ClassLoader.java:306)

at java.lang.ClassLoader.loadClass(ClassLoader.java:247)

at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:619)

at org.eclipse.equinox.launcher.Main.basicRun(Main.java:577)

at org.eclipse.equinox.launcher.Main.run(Main.java:1410)

at com.arm.workbench.Hook.run(Hook.java:463)

I've tried uninstalling, rebooting my PC and re-installing, but still get this error. It looks like I'm missing some jar files, but the files are there. Comparing systems to a co-worker who got 13.1 working, we can see that the files are in the right place as well.

I think there must be a residual file hanging around somewhere that's confusing things, but I don't know where to look.

Any ideas?