This is an issue which has occurred before.
IIRC there was a simple option to tick to fix this.
A quick search on the forums doesn’t get my any results I wanted.
I believe it was something about users in vista, restricted to ask the user before allowing network access. However, firefly did not support this prompting for access, which caused it to fail.
I do know of one option in Control Panel -> Users that turns off all warning messages before opening a program. Maybe that option is the one causing trouble.