First check you are running the latest version of Palringo? Check the version number in Palringo from Menu->Options->About. If not you should point the phone's web browser at palringo.mobi to download and install the latest version.
Palringo works best if you have a BIS (BlackBerry Internet Services) enabled phone but if you don't you should still be able to connect by changing a few settings.
Find these in Options -> Advanced Options -> TCP.
As for what to enter, well this depends on your location and network carrier. The guys over at Opera Mini have done a good job of listing a number of configurations. Check their website here www.operamini.com/help/connect.
If your network isn't listed try our Forum or a search of the internet should get you what you're after.