Arc GIS 9.3 MXD is not saving

[madhurao1]

I am using ArcGIS 9.3 version, My MXD is creating problem. If i save the mxd with shapefiles and IDW interapolation maps, and i close the mxd only shapefiles is visible IDW maps is not visible but the IDW layer in TOC is visible.

pls do the needful.