You can only use LW 5 on an intel machine made in past couple of years. LW site will auto detect your system I believe. One way to check if your system is compatible is go to Java preferences, if you do not have Java 1.6 (Java 6) listed then your computer is not able to use LW 5. Setting up Java for Leopard (see 2nd image)

Make sure LW is set as an exception in OSX's firewall.

What kind of wireless system do you have? Brand & model. This might be causing a firewall effect, most wireless systems tend to.

Change your gnutella.net file over to a new one.

thanks for your reply - i've gone and checked my java settings as you said and it says i have java SE 6 - 64 and 32 bit is this right?
hmm now this is taking a guess but........... my internet connection is a ******* wireless usb stick with vodafone is that what you mean? i dont have a router or modem like i did when i had broadband.

two last things;

how do i change the firewall settings as an exception and change my gnutella.net files?
sorry i know this is probably really simple for you but it may as well be in japanese to me!