I am trying to assign a selected Audience to a SharePoint SPS 2003
Survey and in the 'Select a Portal Area for this survey' option I
assign this Audience Group (specific classroom user group) while
removing the default All Portal Users.

The system allows me to put my Audience Group to the Selected
Audiences box and remove the All Portal Users and I say OK to to
accept it.

When I come back to view it, the system defaults back to All Portal
Users in the Selected Audiences box and the Audience Group is back in
the left hand box - Available Audiences.

Please help explain why I am not able to assign the survey to a
particular Audience Group and not the whole Portal?