Dan,
I'm using the exact same version of Netscape, also with a dial-up 28.8
I've had those problems a few times, but it's nowhere near routine for me.
Maybe you should try re-installing Netscape? Sorry I can't be of more help.
"Alcohol is like love. The first kiss is magic, the second is intimate, the
third is routine. After that you take the girl's clothes off."
--Raymond Chandler