I suspect that the local file browser interface within FlashFXP is loading a shell extension that uses OpenSSL and its linked against a different version then the one we use in FlashFXP.
If the error occurred within the FlashFXP codebase the error would have appeared on startup, as we make sure each of required API for OpenSSL are available before trying to use them.
In addition we don't use OpenSSL for anything related to the local browser.
http://msdn.microsoft.com/en-us/library/ms682586