I'm getting "Invalid accesst to memory" errors not only after resuming, but it happens as well when you disconnect your connection (either turn off wifi or just plug off lan cable) and trying to reconnect after switching your connections back on. It happens with every version i tried. Really very annoying problem. I'm using Win7 32bit, I don't remember it happened when i was using WinXP.
Can you send me an email, so I can send you back a debug version of WinSCP to track the problem? Please include link back to this topic in your email. Also note in this topic that you have sent the email. Thanks.