The sound cutting out indicates some other program has popped up a
window (which you can't see because it's hidden behind GPL's window)
and grabbed focus away from GPL. This other window is probably a dialog
box saying "You've been idle for a while, so I've disconnected you from
the Internet. Would you like to reconnect?", or some such. I believe
that Windows' notion of "idle" is rather, ahem, misguided, and it's
closing your Internet connection. Error 10049 means "address is not
available", which fits nicely with the fact that your modem
disconnects.
On Win95 (translate if necessary on Win98)...Double click "My
Computer". Double click Dial-Up Networking...Right click on your
Internet connection, and select Properties. In the Connect Using box
at the bottom, hit Configure. Select the Connection tab. In the Call
preferences section, make sure "Disconnect a call if idle for more than
N mins" is NOT checked. Just be sure to manually disconnect when
you're done, lest you run up unexpected connect charges.
Randy