If you haven't already tried it, I would recommened installing the latest driver for the Dell Wireless 350 Bluetooth adapter. You can download it from the Dell support website (http://support.dell.com
then click on Downloads and specify your system). The driver is listed under Network Adapters.
You might need to uninstall the current driver first, on the off chance that causes problems. It shouldn't, as the drivers have improved a great deal since bluetooth was first introduced on the Dell notebooks.
What is the error message you receive? That would help identify what the actual problem is.