用命令流更改Workbench中的单元报错，该如何处理？
在分析某空间桁架架构时需要把部分beam杆件转换为link180单元，插入以下命令流：
et,matid,link180
SECTYPE, 1,link, ctube, , 0
SECDATA,44.5,48
用该命令流对结构单元进行修改后，分析时出现以下报错：
*** ERROR *** CP = 1.578 TIME= 13:59:38
Beam element 1 references section 1 which is not a beam section.
*** ERROR *** CP = 1.578 TIME= 13:59:38
Beam element 2 references section 1 which is not a beam section.
*** ERROR *** CP = 1.578 TIME= 13:59:38
Beam element 3 references section 1 which is not a beam section.
*** ERROR *** CP = 1.578 TIME= 13:59:38
Beam element 4 references section 1 which is not a beam section.
*** ERROR *** CP = 1.578 TIME= 13:59:38
Beam element 5 references section 1 which is not a beam section.
*** ERROR *** CP = 1.578 TIME= 13:59:38
Beam element 6 references section 1 which is not a beam section.
*** ERROR *** CP = 1.578 TIME= 13:59:38
Beam element 7 references section 1 which is not a beam section.
*** ERROR *** CP = 1.578 TIME= 13:59:38
Beam element 8 references section 1 which is not a beam section.
*** ERROR *** CP = 1.578 TIME= 13:59:38
Beam element 9 references section 1 which is not a beam section.
希望前辈们能指点后辈一下，十分感谢，以下是workbench分析文件。
