Make sure you have the mIRC scripts loaded properly. You might want to check if it's reading the data from the request to the PHP file. Instead of storing it in MySQL as it currently does, use
fopen(), fwrite() and fclose() to write a file on your server from the request.
Although my recommendation is to install an eggdrop, and use my far better eggdrop version of this hack. If you run a localhost, e.g. if you run Apache (for maybe purposes of running a test vBulletin board) and it works, then there is no reason you couldn't install an eggdrop (or windrop for win32).