Had the same problem, after upgrading from Froyo to Gingerbread (Huawei x5) i lost all data connection. When typing *#*#4636#*#* State: DcInactiveState disconnected with last try at "time" fail because NONE.
All the settings were correct APN etc...
The solution for my problem was - new sim card (my sim card was from 2001). All worked fine before the upgrade.
Hope that helps.