As you have searched the forum for two weeks I guess you have looked at, and read, all of the posts in the Can't DCC Send
thread? Also, take a look at kareno.net
linksys help page.
The general idea is that you forward atleast two ports on your router, preferably in the range of the default range in mIRC - that being 1024-5000. You then need to set the same ports in your DCC port options:ALT+O > Connect > Options > [Advanced..]
You may also want to browse the LinkSys support page
for help with any features in the router that you do not understand.