DW CS5.5 under Windows7 64 bit.
Security Assist has been removed and reinstalled a lot lately since it is recommended to be installed last and there has been the activity with new versions of Design Extender & Security Assist.
Just out of curiosity I removed & reinstalleed it again and tried using Generate Random Password, still no file created.
I find WA_RandomPassword.php under WA_SecurityAssist.
Thanks for sending the file.