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What OS are you running on it?

Have you tried plugging in an ethernet cable from your router/modem and then having "Using DHCP" selected in either the "TCP/IP" control pannel on Classic or the "Network" system preferences in Mac OS X? I was able to get a Powerbook G3 running OS 8.6 online by simply doing that.

Depending on what system you are running, you might need an alternative browser like iCab or Classila. The old Internet Explorers and Netscape Navigators are usually unsupported at this point for most sites.

Instead of uploading to the internet from your old machine, maybe try plugging a USB thumb drive formatted for mac up to it and then put the files on there. That might be an easier way to get the files from your old machine to the new one.
 
We are missing quite a few helpful details from you. Namely:

What OS version are you running?
What method are you using to connect to the internet?
Where are you trying to upload these files to?

And a bit more description would be lovely; what have you tried already, and what issues did you have in your attempts?
 
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