FTP fails

I upgraded to build 985 yesterday and since then I haven't been able get SmartFTP to work. When I tell it to connect to a site it always fails with the message:
"An attempt was made to access a socket in a way forbidden by its access permissions."
The command line FTP (in Win XP Pro) doesn't have any problems. I turned the XP firewall off just to see if that was getting in the way but SmartFTP still prints that error.
In desperation I downloaded and installed cuteFTP and it fails in essentially the same way, although it reports the problem as socket error #10013.
Anyone know what's causing this error?

Best Wishes
Pete

Please search the forum about issues with one of the lastest (April) Win XP security hotfixes.

Thanks for the suggestion about hotfixes. Although I still haven't found the exact cause of the problem, I have restored the system to a point about a week ago when SmartFTP was working and I'm just going to go with that.

Pete