There were several messages appeared in this group around "installing
QFEs on Vista PC." Recently I also came up with this same problem and
found the KB950793 article:

When installing Windows Embedded CE 6.0 QFE on Windows Vista user gets
error and QFE can not be installed
http://support.microsoft.com/kb/950793/en-us

This way I successfully installed the particular QFE - Cumulative
Product Update Rollup Package (through 12-31-2007).

Hope this helps!

---- Hiroyuki NAKAYAMA ----