630 - 633 Error.
On windows 98 based machine You would receive this error in this format - Error 633: The modem is not installed or configured for Dial-Up Networking. To check your modem configuration, double-click the Modems icon in Control Panel
When you try to use your modem on a Windows XP-based computer, you may receive an error message similar to the following: Error 633 Modem is already in use.
On windows 98 based machine You would receive this error in this format : 630 - The port was disconnected due to hardware failure. Error 630: The computer is not receiving a response from the modem. Check that the modem is plugged in, and if necessary, turn the modem off, and then turn it back on.
Windows 2000 & XP - This error can occur if another application or process is monitoring the modem port.
These errors have been observed mostly appearing on the Windows 98 machines only. No case of such error on Windows XP or on Windows 2K has been reported to this office till date. However, removing the PPPoE Setup from the Add/Remove Programs in Control Panel and re-installing the same has gracefully solved the problem. However, If the same fault is observed on Windows XP, we suggest re-installing the connection.