In Windows Vista, Windows Meeting Space may be unable to detect the peer computer and may be unable to establish the connection over a private ad hoc wireless network
On a Windows Vista-based computer, you establish a Windows Meeting Space session that uses the Create a private ad hoc wireless network option. Then, a remote Windows Vista-based peer computer tries to join the Windows Meeting Space session. However, Windows Meeting Space may be unable to detect the remote computer and cannot establish the connection to the Windows Meeting Space session.
For more information on this issue, including potential causes, workarounds, and resolutions, see: Microsoft KB Article KB955804.