Excessive buffering while streaming audio can be cause by several things, as listed below:

Your Internet connection is not fast enough to support the speed of the station.  In general, cell networks and modems cannot play stations of 64kbps or higher.

The ShoutCast server is overloaded.  If there are too many users, some ShoutCast stations can become overloaded and can't keep up with all the listeners. Try accessing the stations via the TreoBits website at www.treobits.com or another popular site is www.di.fm. Their servers tend to be less over-loaded than the ShoutCast servers.

You may not have enough coverage to play streaming audio.  Make sure that you have a good signal; streaming generally requires a stronger signal than web browsing because of the large amount of data that your handheld receives.

The cellular network (or local wireless network) may be overloaded.  If there are too many users trying to access the wireless network, the data speed will slow down.  Try again during non-peak periods or try a lower bitrate station.

There may be temporary network problems between you and the server.  There are typically a dozen or more network servers between you and a ShoutCast server; if any of these servers is having trouble, they could cause a slowdown in the network.