In AutoCAD 2002 (or older), you have used internal icons of AutoCAD commands (e.g. ICON_16_DIMRAD) in your customized user menus. These icons do not work now (are replaced by question marks or clouds) in higher AutoCAD versions (2004, 2005, 2006, 2007...).
Internal icon names have changed in menu files of the version 2004 (and higher) - they are now in the format RCDATA_16_xxxxxx.
When you transfer your menus, change (e.g.):
ID_Dimradius [_Button("Radius dimension",ICON_16_DIMRAD,ICON_32_DIMRAD)]^C^C_dimradius
ID_Dimradius [_Button("Radius dimension","RCDATA_16_DIMRAD","RCDATA_16_DIMRAD")]^C^C_dimradius