Unable to register on selected network. Choose another network, or disconnect your data connection and try again

or Unable to read setting from network. Try viewing settings later, or dissconnect data connection and try again

I was in Johor Bahru and was surprised that my HTC Touch diamond was not able to connect to their local network. Despite changing to manual network settings, soft resetting my phone etc, I still couldn't get it to work.

After searching my phone settings for a long time, I finally found out that it is due to the HSPDA connection.

I had to turn off the HSPDA option under "settings" -> "Advanced Network"

Don't you just hate it when the error messages mislead you to other directions which doesn't solve the problem?