If the customer is logged on locally to the computer as an administrator with the
following command line the install works.

"Sun JRE 1.4.2_10\j2re-1_4_2_10-windows-i586-p.exe" /s /v"/qn
IEXPLORER=0 ADDLOCAL=ALL JAVAUPDATE=0 WEBSTARTICON=0 EULA=1 /L*v
c:\temp\Jre.log"

We've tried with both IEXPLORER=0 and IEXPLORER=1.

If the cu is logged onto the computer as a user and use runas: with her admin
credentials the above command line does not work and IE will not register the Java Plugin, hence Java applets will not work in IE.