Users may try to add an attachment to an incident. They browser for the file and type in a title. Then they click the Save button. After clicking Save the attachment object is saved, except the file is missing.
This can be a problem with permissions on the TPS server. When the files are uploaded they are stored in the temporary directory on the server. Users may not have sufficient privileges on the temp folder and so the server is unable to create the temporary file and finish the upload.
To fix this problem give everyone modify permissions to the temp folder on the TPS server.