Visual Dataflex is shite. I remember we evaluated this back in 1995? when it first came out (at the same time as Delphi 1) and it was crap then. Maybe it is better now, but it's still very niche in the professional sector. VDF was big once, back in the early 90s and on UNIX especially, but jesus.. not now..
I`d also have to question the sanity of someone who wants to employ a developer who doesn`t know the tools / language he's developing in (sorry - no offence there, but it's not practical)