i had the same logs as you, i fixed it by changing firewall rules.
this is what my router log looked like when the random ports where occuring
Friday April 17, 2009 19:33:44 Unrecognized attempt blocked from 59.113.164.120:25082 to [my WAN IP] UDP:48954
Friday April 17, 2009 19:34:25 TX TCP reset for 192.168.0.2(1977) -> 192.168.0.1(80)
Friday April 17, 2009 19:34:25 TX TCP reset for 192.168.0.2(1978) -> 192.168.0.1(80)
Friday April 17, 2009 19:34:58 Unrecognized attempt blocked from 119.117.108.210:19450 to [my WAN IP] UDP:48954

unfortunately i dont know if you have the same settings on you router, hope this helps.
note: after i did this firewall configuration the random port messages were gone from the router log.