See if the information in this article helps.
Courtesy of Ramesh Srinivasan, MS-MVP
How to reinstall Netmeeting in Windows XP
http://windowsxp.mvps.org/netmeet.htm
If that doesn't fix the problem, you might want to search your hard drive for
conf.exe. Make sure you've configured search to include system folders, hidden
folders, and subfolders under More advanced options. If you find a copy in a
location other than the Program Files\NetMeeting folder, see if it works. If it
does, copy it to the NetMeeting folder to replace the one that doesn't work.
If that still doesn't solve the problem, check the version number of conf.exe in
the NetMeeting folder. You can do this by right clicking the file, selecting
Properties from the menu, and clicking on the Version tab. Post back and let me
know what version you have. Also, include information on what version of Windows
XP is installed on your computer including the service pack level.
Nepatsfan