You could use the installer/uninstaller that comes with to remove and reinstall everything in the network group
I had this distro about a year ago - I noticed that if I fiddled the network setting too much everything seemed to jam up. I'd have to remove all the services and start from scratch - easier than trying to debug what I did. I think, but do not know, that some settings get cached somewhere and don't go away until the board is totally clear.
Before you get that far tho - try clearing all network and restarting. Also make sure that /dev/ttyS1 is really still your modem by sending a string to it and watching the pretty lights. That's right - back to basics.
However, you may find you adsl works after the reset
BTW: error 8 is usually a failed connection - (no dialtone in dialup) check/replace your cables. Get your phone company to test the phone line and the isp to test the adsl setup for you. (Explain you are getting "no connection" errors.)