I've been experiencing a similar issue but not when logging in.

I have 3 machines which all run FFXIV perfectly fine. 1 of which is my monster PC i recently built that can play the game very well with the settings turned up pretty high.. but 1 of the others may need to a bit on the low side for it to run well.. either way they run the game fine..

Well, anyway.. at random times, the game will crash for almost no reason at all. sometimes it happens when i'm in the middle of a leve, other times it's when i'm just standing there. more recently it's been happening when i zone in and out of places that require the game to load another area.

being that it was happening on all 3 of my machines i didn't suspect it to be an installation error or problem with the software requiring a re-install but could be wrong.

any support would be much appreciated

the machines are all running Windows 7 Ultimate x64 all of which have the most recent driver updates and windows updates

Builds

Desktop
i7 2600
16gb of DDR3 ram
Radeon HD 6900

Laptop 1 (XPS M1730)
Intel Core 2 Extreme X7900
6gb of DDR2 ram
Nvidia GeForce 8700M-GT (recently replaced by dell ^^ )

Laptop 2 (XPS L702x)
i7 2630QM
6gb of DDR3 ram
Nvidia GeForce GT 550M