Dear Marcus,
I assume that in the past Fragstats worked and now suddenly it does not work and gives you the error you posted.
Since it worked before (and it works for just about everybody else) one possible reason is that you may have installed something else in the meantime, most likely a 32-bit application that came with its own GDAL libraries and the windows loader sees them first and is trying to load them upon Fragstats execution.
It should not happen however because Fragstats comes with these libraries bundled in its start-up folder and they should have priority in loading.
Another, more likely reason is that in the meantime you (or Microsoft) activated the so called Windows Smart App Control which is blocking the application from loading its own bundled files because it considers them "untrusted".
If you feel comfortable with managing your windows security you can disable the Smart App Control to regain the functionality, or you can ask your system admin to help with it.
Best regards,
Eduard Ene
