Export nodes from Drupal 4?
I'm assuming you're on a shared server. Here are some options.

Option 1 - Downgrade PHP.
Although it might not be the safest choice, as both the PHP and Drupal is probably no longer supported, you can do the following.


Some hosts allow to specify a different PHP version in php.ini.
Rent a cheap VPS, which will allow you to set the PHP version.
Some shared hosts specialize with older PHP versions, make a switch.


Option 2 - Use backup and migrate modules.
There are a number of backup and migrate drupal modules which will make the migrating process easier. This would be a safer choice, but the downside, is that you'll loose your theme and you might have to upgrade to ->5, ->6 and only then to ->7. Here are a few modules to look at


Backup and Migrate
Backup


Option 3 - Start from scratch, import in bulk.
It's both safe and probably the best choice. Set up a new site and a theme. Export the data from the old site, using feeds, or other Drupal modules and import it into the new site using modules like Migrate.

I would advise to upgrade to D7, since the support for D6, not alone D5, will be dropped soon.