I use the latest version (4.1.2), and I've got this message almost every time when I start WINSCP.
I used 4.0.7 (I guess) previously, and I had the same problem, but I saw a BUG report, and the report said the bug fixed in 4.1.1. I think it is not.
If I just start my PC, usually it works, but when I start the program second time, the error comes up.
And after this error message, most of the functionality go dead.
If I can help ....
I use: MS Windows Vista Enterprise