It was Windows 7 Ent 64bit SP1 with Java v19 installed. Upon attempting to uninstall he received the error:
After a bit of digging around I discovered the error was referring to a missing DLL.
By going into the registry and finding the MSI entry I tried an uninstall using the following command:
This was found here: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall - this is a great tip for any app packagers needing to discover the msi registered to a piece of software for uninstalls etc...
Again I received the same error message. To enable error logging I added /L javauninst.log and discovered it was missing the "regutils.dll" located here: C:\Program Files (x86)\Java\jre6\bin
I copied the file across from an existing machine and voilà - it worked !
Another Java/MSI quirk but non the less slightly perplexing to say the least.
Hope this helps someone else sometime...