往ADS中导入GDS文件时的出的错，请大神们帮帮忙。不胜感激！

Using layers file "E:/users/default/UWBlna_inductor1_prj/lay091202.lay".
Wed Mar 24 08:47:54 2010
Reading GDSII file "E:/users/default/UWBlna_inductor1_prj/UWBlna_inductor1.gds".
WARNING: Failed to create a design for the GDSII structure "UWBlna_inductor1" because the design "E:\users\default\UWBlna_inductor1_prj\networks\UWBlna_inductor1" is currently open.
The open design will be used for the import. To avoid this warning message in the future close all designs before performing an import.
WARNING: Found a structure reference (SREF) referenced within itself in the "UWBlna_inductor1" structure. This SREF will be ignored
ERROR: Invalid SREF element in 'UWBlna_inductor1' structure The corresponding GDSII element was ignored and will not appear in the design named "UWBlna_inductor1".
WARNING: Detected more than 1 top level structure (i.e. multiple GDSII structures
were found that are not referenced in other structures). The structure "uwblna_inductor1"
will be used as the top design.
Import Complete - 3 warnings, 1 error