Psiphre, I believe the problem is related to your video card.
Just doing a quick google search I discovered that the maximum memory for the Radeon x1400 is 256MB, which is far lower than the minimum system requirements of 512MB.

I still don't see why this would prevent you from launching the game though. It would be slow as all hell, but you should be able to at least get in-game. The only thing I can think of that may fix your problem is a driver update from ATI.

ATI is notorious for having terrible drivers that behave in strange ways when updated directly, so it is recommended you uninstall your current drivers before updating.

Is it possible that you have a Radeon x1400 with more memory than the average card? My information on it is strictly limited to what I can find through searches, and nothing I've seen so far related to the x1400 suggests that any company ever put out an enhanced version.

One last thing, if you do have a regular, non-enhanced Radeon x1400 with only 256MB of ram... lets just say that a Radeon card with that much ram can barely run FFXI on low settings, let alone a game like FFXIV, which is much more GPU intensive than CPU intensive. =\