DM Manager won't sync

I have DM 4.5 installed on 2 laptops- everything works perfectly. I then installed on desktop but when I try to sync contacts it says it must be connected to the internet and to try again. The computer definately is on the internet, I tried turning off the firewall but nothing helps.
Anyone hae any ideas? All 3 computers are on the same network.

You may want to uninstall then reinstall.

Here's the latest version for PC: https://www.blackberry.com/Downloads...55F8366F4ED9E9

Thanks for the suggestion, already tried that. Also tried 4.6 but still no luck