Its nothing to worry about
The modem's DHCP server is active when the modem is in
"PPP is on the modem" mode.
To avoid that XP system event log message:
The modem's DHCP server is inactive when the modem's mode is in
"PPP is on the computer"
OR
"Bridged Mode (PPPoE is not used)".
OR
You could change your computers TCP/IP properties to match this
Image Depending on what you do with your computer this address may be better 192.168.1.64