Hi,
so try another tweaker :
ActiveTweak v1.3 which should work better i think (much more options)
source :
http://pocketpcapps.net/default.aspx
launch
runningAS >>
Shutdown then
restart
maybe you could also
delete partnership
When the popup menu appears on your mobile, it's important to click on
ActiveSync then
ok (or
ok directly if ActivSync is already checked)
If it doesn't still work then try to uninstall ActiveSync and reboot your computer and re-install it
^^