Just for anyone else facing this problem:
I fixed this issue by using the latest SP available at this point in time (14.2.5).
I also had to install the certificate from salesforce into the jre keystore. I got the certificate from Setup-> Develop ->API in Salesforce.
There is a good post on how to do this here:
https://bobj-board.org/t/228816
Cheers 
drserguey (BOB member since 2010-03-01)