Icable modem is malfunction again Feb. 2011

I cannot access internet suddently approximately at 21:40 Tuseday, Feb. 8 2011.
temperature is 19c, relative humidity is 9x.
I can access it agian on 08:00 Thursday, Feb. 10 2011.
temperature is 16, relative humidity is 6x
It shows that if the relative humidity is high, the modem does not work.
At recent years, it does not work at spring several times.