WLM 9 Beta Install Problems

i'm trying install my WLM 9, but i keep receiving the
following message "service messenger sharing folders USN jornal reader
service' (usnjsvc) could not be installed. verify that you have sufficient
privileges to install system services.....
Thats the error that appears when i try to install the WLM 9 beta !
What should i do ?
Answer #1
Are you using an account with administrative privileges mate? Also, have you tried ignoring that error and trying to move on with the installation?
Answer #2
Yes im using a Admin account !
I cant ignore it because it only gives me 2 options : RETRY and CANCEL !