Associative file error, is a common problem if your programming to attach a file without an extension in your send email attachment. This function module is 'SO_NEW_DOCUMENT_ATT_SEND_API1'.
1. Go to Control Panel, Default Program, Set Associative. Check if your file is supported.
2. If your file is supported in Set Associative, the go to your coding, particularly at parameter OBJECT_HEADER. Make sure your file has an extension otherwise the above error popup will appear.
Is sky the limit... associative error