Since you can't send files but you could before, then that confirms that your fserve problem is very likely caused by the same thing that blocks your dcc-send, so you can likely fix both by fixing 1 or the other.
Did you confirm that this still shows the same local local ip address that your router is forwarding your dcc send ports to: /run command /k ipconfig /all
If your local ip is being dynamically assigned each time you reboot, it's possible you need to simply fix the router to point at ip adress ending with .102 instead of .101 for example. I assume you've already been to
http://www.portforward.comThe lazy way to enable both is to use mIRC 6.17-or-higher's passive-send feature "/dcc passive on", but that isn't always a good fix, because it requires the receiver to have open ports instead of the sender. This means you'll be able to send to someone else who has opened their dcc-send ports, but someone else who has the exact same dcc-send problems as you - would not be able to send to each other.