Unable to add ports in port mapping section of the router page

[Sinkyboy2000]

I am trying to set up an FTP server on a machine on my network. When I go in to the router settings and then to IPv4 Port Mapping, I can click add to open a dialogue box to "Add Port Mapping". I can put in all the details until it asks me about "Public Port" and "Local Port". When I type, nothing appears in those boxes, so I can't complete the entry. 

[Jayach]

I have no problems entering data into those fields, so it should definitely work for you.

I suggest you try a factory reset on the router, but first make a note of the firmware level, then remove the DSL cable from the router and select Settings - Configuration - Factory Settings. Once it had rebooted plug the DSL cable back in. 

In my experience that is the only way to get a new firmware, if one is due. (the firmware update checker simply doesn't work)

Let us know if it works.