Unsupported IPSW issue resolved. RedSn0w could not recognize the device and could not check the IPSW for authenticity for a match with the device. For anyone that has a similar issue (should only be on Windows PC's), if your device is plugged in and RedSn0w says that the IPSW is unsupported and you know it's supported in that version of RedSn0w, navigate to C:\Program Files\Common Files\Apple\Apple Application Support\ and copy-and-paste the SQLite3.dll file into your RedSn0w folder. Re-open RedSn0w now and it should now be recognized.
For 64 bit users, the directory is C:\Program Files (x86)\Common FIles\Apple\Apple Application Support\
@Ciansy, you can now upgrade iTunes back to 11.1.4 if you'd like.