Actiontec MD560RD V92 MDC Modem game connect failure

Can only make it part way through an online game connection with modem. It gets through the account login, but it can't connect to the "login server" in SWG, which is where you select a server, and can't get to the character selection in DAOC, which is after selecting a server. What I mean by "can't connect to" is that the modem thinks its lost its connection, and gives me a redial option. Service provider is earthlink (if that matters).

Windows XP

The following does work fine:
connecting through wireless or ethernet (modem/modem setup specific problem)
connecting through modem on different computer on same phone line (phone line is fine)

I've tried the following, usually turning things back on if it doesn't fix to try the next:
updated modem driver from dell support (if there was one, don't remember)
disabbling firewall
lowering max speed to 9600
disabling hardware flow control
disabling modem error control
disabling modem compression
disabling software compression
disabling LCP extensions
disabling IP header compression
enable negotiate multi-line for single link connections
enable NetBIOS over TCP/IP (was originally set to disabled, and "default" is not selectable)
turning off V92 extensions (AT+MS=V90 or something like that)

The rest of my tries I don't remember at the moment.

oddities of my machine:
dual boot linux/Windows XP
May even be non-Dell Windows (can't remember)
Other problem in case its realted: system occasionally freezes for a couple seconds if i leave the "windows time" service on. This might not be a problem when connected to LAN (I let someone set some configurations to work on department LAN, which i think relies on one of those time-stamping security setups, but it might be my imagination that has generated this connection)