artc,
In the absence of more information about your setup, it’s hard to know whether or not the most recent release fixes the issue that you were encountering, but there were some outstanding issues with PHP 5.4 in particular that could cause fatal errors; if that is the issue you were encountering, the most recent release, 2012.1212, fixes the issue. If that’s not the issue you were encountering, then I’d be happy to take a look at the problem if you can let me know something about what version of FWP you downloaded, what version of WordPress you were attempting to use it with, and what version of PHP your web hosting environment was running.
In any case, the recent update that fixes the PHP 5.4 compatibility issue is now available at https://www.ads-software.com/extend/plugins/feedwordpress/
Thanks,
-C