Thanks
I tried numerous date format combinations, (I even tried different time formats), re-installing Firefox to ensure I had the latest version, the same with Silverlight. An issue I had with Silverlight is that I had deleted SkyGo from the 'Permissions' tab so whenever I installed another version some how it remembered that SkyGo had been deleted from the 'Permissions'. I had to do a number of system restores to rectify this. Unfortunately I don't have the necessary I.T skills to edit the coding for Silverlight in my laptop's programme files.
My next thought was to try Internet Explorer, so I attempted to install the latest version. To do this I needed to update my Vista system to Service Pack 2 which I did overnight. Once complete I was able to install the latest version of Internet Explorer and hey presto Silverlight works, no error messages. Hope I don't have to go through this again in a hurry.