One will update-one won't?

Just downloaded 3.5.1 and installed on Win.XP laptop and Win.98se desktop. Had 3.4 version on both and was working fine.
Now the XP machine is working fine, however I get a "cannot establish a connection to download" prompt on the Win. 98se machine when I attempt to update.
Have a DSL connection with both connected to a Linksys router and Westell modem.
I have scanned for spyware, tried the "use alternative download method" checkbox, rebooted the router and modem, disabled the antivirus etc.
Still not having any luck updating the 98se machine. Win.XP is working fine.
Thanks for any help--Milt