Yep, You Can Delete Those Program Listings...Tried This Yet?
You may still need to remove the registry entries but be sure to check for all other versions of Java that may be installed in "Add/Remove Programs". Then remove the Program Files listings you've mentioned. Once that's done, then run Revo again to see if any remnants remain..
Once that's done, click on the link below, then select to to download the OFFLINE Java6 Update 31 installer to your desktop. Once there, run the offline installer.
Hope this helps.