1) Do you use #s to navigate your app?
The default gingerbread browser would break the currently active connections when pressing the back button. I fear we can't prevent that.

2) GPRS may be slow enough for the polling timeout to be triggered
I do not really understand what can be the root cause of your issue, I can see it streaming on a very slow Huawei Ideos and on a faster Desire HD both running gingerbread.
Any chance to test it on a different wifi or on a different smartphone to understand if the issue is on the mobile or on the network?