I downloaded and installed the DirectFTP 6.5.2 Beta and received the following message (at the end of the install):

There has been an error.
Error running C:\Program Files\CoffeeCup
Software\DirectFTP-6.5.2/DirectFTP.exe :child killed: SIGABRT
The application will exit now

The application appears to have installed correctly and comes up fine.

Sorry - forgot to include that I am installing it on Vista Home Premium, SP1.