ok, fixed that bit.
I had to use hex as the value in the reg file;
"ConfigUiPath"=hex(2):43,00,3a,00,5c,00,57,00,49,00,4e,00,44,00,4f,00,57,\
00,53,00,5c,00,53,00,79,00,73,00,74,00,65,00,6d,00,33,00,32,00,5c,00,72,00,\
61,00,73,00,74,00,6c,00,73,00,2e,00,64,00,6c,00,6c,00,00,00
Only trouble now is I still get the same error when trying to install the next version.
Grrrrrrrr