ASP: First upload file .... Invalid process call or parameter: 'midb'. For more information, see statement error.

After ASP uploads a file and submits a form, an error message such as "invalid process call or parameter: 'midb'" appears.
After debugging for half a day, the root cause of the error cannot be found. Baidu finds the root cause of the error.
I forgot to write enctype = "multipart/form-Data" in <form>.

<Form name = "formsousuo" Action = "yuangongupdate. asp" method = "Post" enctype = "multipart/form-Data">

Multipart/form-data is used to upload files and cannot be deleted.
The default value is application/X-urlencode-formdata or something.

Other usage needs to be further studied...