I don't know enough about FlashMX to really say much, but I'll try anyway.

I see two basic ways (well, perhaps three or four, but two applicable ways) to get the data from the flash form to the perl script. Either the perl script can be accessable via HTTP (which doesn't neccessarly mean running a full webserver, but I'll get to that in a moment), or you can set up the frontend (the FlashMX program) to run the perl program with some arguments. They each have their own set of problems.

I suspect running a webserver is what you want to do. You can either set up a web server, and get your script to run as a CGI, or you can write a web server in perl. Either is fairly easy -- Apache and IIS are both easy to setup (for a simple server like this), and HTTP::Daemon is rather easy to use. Doing it this way avoids the contention and locking problems you'd have with doing everything on the client side.

You can also have the frontend simply call the backend with a bunch of parameters. However, if you do it this way, you'll end up with a long commandline, which windows may not like. Also, you'll have to deal with locking issues (file locking over a network isn't the easiest thing in the world, though you do have the advantage of a relitavely homogonious installed base, and only one file server). However, you won't have the administrative and security problems associated with yet another server.

I'm sure I'm forgetting somthing, but I normaly am. For that matter, "am" can refer to either being sure, or forgetting somthing... no what did I do with my brain again? It's around here somewhere, I'm sure.