Just to confirm, are you using the same PC that you used to Root your Kindle Fire with? In other words, have you used ADB with this PC before? If it is, then a Factory cable is I believe the only way out.
You can try to make one, or I piked one up on eBay for £3 including delivery. I have read of someone destroying one of the pins on their Kindle due to connecting the wrong wires up, so be careful and take your time doing it. Double check everything.
We could do with a step by step guide for recovering a Kindle in a loop, as there doesn't seem to be one and they seem to be getting soft bricked quite often at the minute.