HOWTO : Configure Nokia 6600 phone with Bluetooth and PC Suite for successful communications : (This was tested and verified on two computers)
YMMV - do try to use the latest software tho...
1. On a preferable clean system (if the system is not a clean system, skip to step 11) start the Bluetooth installation. Configure the software if needed.
2. Once the Bluetooth software installs successfully, pair the computer and phone. Don't do anything further. You MUST have a successful pairing, otherwise you will NOT be successful.
3. Reboot.
4. Install the latest Nokia PC Suite software. Make sure to tick the 'Install SDK' component as well.
5. Reboot when the installer asks you to do so.
6. Right-click on the Bluetooth icon in the system tray, open Advanced Configuration, and select the Local Services and Client Applications tab. (This may vary from software to software, I'm using the WIDCOMM Bluetooth Software 1.4.2 build 10 package).
7. Make a note of the value of the Bluetooth serial port in use for each tab. One port for sending, other for receiving. (well, it looks like it's using two ports, to be on the safe side, select both).
8. Right-click on the MRouter icon, select Properties, and deselect the Bluetooth - COM500 entry, and select the two Bluetooth ports that was listed in step 7.
9. Right-click on the blue 'B' in the system tray, click on Quick Connect, select Bluetooth Serial Port, select the paired phone.
10. The connection will throw an error out, but the PC Suite will connect successfully. Go figure. As long as it works... feh.
You can now successfully send and receive files, pictures, music, movies and pr0n (oops) to and from your phone...
Should you want to disconnect, right-click on the Bluetooth icon, and select 'Stop the Bluetooth device'.
Remember to switch off Bluetooth on your phone once finished.
11. On a "dirty" system :
--- This means a system which have the Bluetooth software and Nokia PC Suite already installed - uninstall these two first. Then, after disabling your firewall and Anti-virus, reinstall the applications and see if you're successful in connecting.
Also, make sure that you've got a working USB port...

chances are if the Bluetooth software does not pick up the dongle, try inserting the dongle into another port, or another PC.
Should you be successful, disconnect from the phone, start the firewall and try connecting again. If this fails, the firewall is giving problems.
Should you be successful with the firewall enabled, disconnect from the phone again, enable your anti-virus software and try connecting again. If this fails, then the anti-virus software is blocking something.
Remember that other USB devices and software might also be interfering with your Bluetooth connection. If you still have problems, try restarting Windows with no running programs and see if that fixes it.
Regards