A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
I'm sure you will have checked that there is disk space available where the file will be put and where Excel might hold its temporary files.
If you open Excel can you open previously created workbooks and save copies elsewhere?
Does restarting the computer resolve the issue?
Error 1004 is a generic error used by Excel/VBA when a macro hits a problem.
If QPort always translates error 1004 to the message you have reported then it could be misleading.
Have any updates been installed since it last worked?
Does restoring the computer to a restore point before the last update resolve the issue?