I can send to others and myself without doing anything different (no need to use /localinfo). Perhaps that has to do with the router? Perhaps related to NAT? I know some routers seem to make it more of a pain to send files to yourself. I don't know. I have 2 routers and both work fine sending to others or myself without making any changes besides just having the ports forwarded. Either way, it's usually a good idea to test sending to others before worrying about whether or not you can send to yourself.
@subnet: In most cases like yours, where one version works and the other doesn't, it's caused by some difference in your settings. Make sure that you have the ports set up to the same ones that you have forwarded in your router. If you have ports 1024-5000 set up in mIRC, then you need the same range in your router. Try disabling Randomize Ports or enabling it. Disable upnp if that is enabled, or you can try enabling it if it's disabled (not all routers work with upnp without making changes to their settings).
