BlackBerry Desktop Software 7.1 ERROR 1723, how do I fix this?

Recently my calender on my Ipad has recently stopped synching with my BB. If I "invite" myself & send a message it will register on the Ipad calender, but otherwise not.
Seen all the stuff about going into Blackberry Desktop Software "Organizer" but when I do that get a statement "Organizer applications on your computer not supported". I've then tried updating/repairing my BlackBerry Desktop Software 7.1 assuming its been corrupted from the BB website and part way through installation it stops and I get ERROR 1723 Action RepairRIMUSBDriver... Can't understand how there can be a problem downloading software from the BlackBerry website!
Help anyone please, I feel like I'm peeling an onion here!