DKU-5 cable installation problem

N's clone DKU-5 cable was not working with his Nokia 6070 phone. For the error mesg on the phone, 'Enhancement not supported'

http://www.susteen.com/support/kb_answers.asp?QuestionId=34

Reasons could be:

1. Phone not supported by cable.
2. No proper driver installed.
3. Cable/phone may be damaged

DKU-5 seems to be compatible with 6070. Checking it out, found that the driver had an issue - Device manager showed that the USB-UART driver had problems.

While reinstalling the driver from driver CD, error message is "name already in use as service name". Uninstalled PC Suite and tried, still no go.
Uninstalled PC Suite, booted safe mode, removed all instances, rebooted safe mode, checked no instances of USB-UART, still the problem persisted.

Some people report that the driver which came with their CD was not working, they downloaded a driver from the manufacturer's website and that worked. But in this case, googling "USB World Technology Inc" gave a driver from driverguide.com which seems to be identical to the one in the CD.

Then, following the tip at linksys forum checked C:\WINDOWS\setupapi.log. It referred to the service "Serenum". Searched with regedit, found the keys, but could not delete them: it says "Unable to delete all specified values". So, stuck till some solution for this is found.