Wireless connection using OSX

Hello everybody. I am hoping that someone can help me with a strange problem I am having connecting my G3 (OSX) to my wireless network. I have a USB D-Link Wireless receiver plugged into the back of the tower. I installed the needed drivers. When I boot up the machine, it detects the appleport, shows the name of the wireless network, says "connected", and shows a progress bar with the current signal strength. But when I pull up Mozilla and try to type in a website I get an error message telling me that I am not connected. Has anyone else experienced this problem before? CJ-