another possibltie is that u may have ca 42 data cable,it is going to repalce the dku 5 in the market , but if u have latest pc suite, it is preinstalled in it so no need for seprate driver. but try installing a driver.
*europe.nokia.com/nokia/0,,81914,00.html
if u dont have the latest pc suite here--
*europe.nokia.com/nokia/0,,79477,00.html#download