same trouble here
I'm using Mac Pro, OS X 10.5.5. (the local firewall is disabled.)
Parallels-Desktop-4.0.3522.205912.dmg
The installation appears to complete, however when running the Parallels Desktop app there is a brief flash on the screen and then nothing happens. If I try to run "Parallels Explorer" then "Unable to find Parallels SDK library." message-box pops up.
Additional note, the "Parallels Network adapter"(s) are available in the "System Preferences -> Network" pane, so at least some portion of the installation seems to have succeeded.
Indeed, upon starting the installation a dialog-box pops up with message "Checking for updates" and then, after it, the installation commences.
Regards to all and thank you.
Last edited: Nov 14, 2008