How to check for locked files?

Hi .. sorry if this has been already discussed .. but urgent need to automate ftp downloads (between remote Unix box and local Win2k3)..figured out the WINSCP scripting possibilities, but is there a way to make sure the remote files are not being accessed (e.g. by other ftp "put") and are ready to download?
The remote Unix is running Proftpd.. just tried to upload a large file to it ..ran a download of this same file at the same time thus resulted in an incomplete local file.

Thanks!

I do not think so.