have also tried with Firefox and IE, but both seem to have the same limitation.
It's not a time limit issue, it's the fact that your Mac is running an outdated Mac OS X Tiger (v10.4.11) and an oudated version of Safari.
Tiger was released on 29 April 2005, so you are about seven years behind today's web browsing technology.
What is it in the newer browser versions that would solve this problem?
Security for starters. And yes, it would solve the problems. Your PBookG4 is about 8 to 9 yrs old? You can't expect aging softwae and hardware to compete with today's technology on the web.
Tiger v10.4 / Leopard v10.5 / Snow Leopard v10.6 / Lion v10.7 and Mountain Lion is not far behind so you are about 4 Mac operating systems behind.
Regards from overcast and a cool SF