[4:06 am] DCC SEND .to. PRIVMSG of versions.txt 1370683332 1035 54291
[4:06 am] DCC SEND from PRIVMSG of versions.txt 1370683332 1035 54291

lol, gotta love how you took the username out, but left something else of far more direct significants in :-) { those that know well know already those that dont Well u just dont need to know }

Anyway, i think your DCC sends are fine from that info above, you dont have any router port changing issues.

You do of course have the issues with slow/dying sends, this problem I dont think is with mirc "loosing track" more like the connection being lost, your end just sits there waiting and waiting, with the speed (an average) decreasing as it waits until its 0.00kbs for a bit then it gives up and says its a fail.

I would suggest you try a dcc chat to this friend and see how long you can mantain that. Maybe in the editbox of the dcc chat run this command to keep something active being said
/timer 0 30 say keep active text at $time

See if this is maintainable. This might not really proove anything, but i think it would be interesting if it does fail at about the same type of time frame.
Its also possable for ISP's to detect the type of connections you have and limit the speed of them, this some "evil" isp's do, and base there right to do so on that "well a dcc send ment you had a server running and thats a breach of your connection agreement" <--- that was tried on me once, i asked them to proove i didnt just dcc send someone a file, which they couldnt do, the problem quickly disapeared.

The other option is to try your end using a different pc and see if dcc send/gets can maintain at high speeds, which would say your OS is dodgy.