Yesterday after posting this thread I've tried to run the Oracle Application on a XP machine. RobThank you for your post and for helping me with this issue.
May not apply to you but worth a check see and do you have any other versions installed? Anything blocking Java plugin from running for any reason? After some very long winded testing (outside profile corruption caused by the imaging boys) I tracked it down to needing the two versions installed to separate folders in the Java folder. I've just a very long and tedious job for the NHS to get some apps working which use Java6 with both Update 17 and update 35 required on the same machine.