Bluetooth Active Sync/passthrough connection timeout ?

[Guest -=S-B-H=-]

Right i sync my phone via bluetooth to my pc and i often use the "pass through" feature so i can surf on my phone at broadband speeds but every 5 or 10 minutes i cant access webpages anymore or the internet full stop, my phone is still connected via active sync but its as if the pass through connection has been closed...

im using a C500 is there some silly fix for this im not aware of ?

thanks

Dave