Well, I managed to transfer one of the problem files to an ftpd on a non-standard port number, but not so far to any server on port 21.
I tried a load of different ftp clients also (there's some scary stuff lurking on some "free" or "shareware" sites!), and they all worked fine. I uninstalled FlashFXP 3 1015 (also removed all of its ancillary files) and installed it again, fresh install, and the problem persisted
So now I've reverted to 2.1, build 924, which I suspect is a very old build. It's running in shareware mode at the moment and works perfectly. It would be nice if it was possible to download the most recent 2.1 build from somewhere, as I don't know what the auto-upgrade in 2.1 did with all the installers it downloaded!
I think I'll hold off on 3 until these more obscure issues have been resolved on XP SP2 systems!
Thanks to all who followed up!
UglyBunz
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