Network Disconnecting when using remotely

when logged on to EITHER logmein.com or gotomypc.com remotely it keeps disconnecting every few min....have replaced switch, nic card , and cables....does not have a router..just a dsl quest modem (their answer to a router) ...what could it be..??  their are other sys. in the network and ALL are just running peer to peer..running xp pro pack 3. 4gb with 4 gb ram and quad amd cpu...using windows firewall with exceptions selected...using avg business ver for antivirus with firewall portion turned off...the only message i get in event viewer is the following:

Event Type:      Error
Event Source:      DCOM
Event Category:      None
Event ID:      10020
Date:            09/07/2012
Time:            2:26:34 PM
User:            N/A
Computer:      ASUS_M3A78-CM_3
Description:
The machine wide Default Launch and Activation security descriptor is invalid. It contains Access

Control Entries with permissions that are invalid. The requested action was therefore not performed.

This security permission can be corrected using the Component Services administrative tool.

For more

information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.