I have just came accross the same issue. I tried all suggestions mentioned in the thread and still had the same issue so I decided to write my own experience.
I recall my database was split into 2 other databases so users could access it at the same time. I then went to one of the split db and tried importing the Excel file there. It WORKED! Then I went to the other split db and imported the Excel file there, it worked again. Finally, I went back to my initial db and imported the Excel file. Bingo, it finally worked w/o any problem!
I recall my database was split into 2 other databases so users could access it at the same time. I then went to one of the split db and tried importing the Excel file there. It WORKED! Then I went to the other split db and imported the Excel file there, it worked again. Finally, I went back to my initial db and imported the Excel file. Bingo, it finally worked w/o any problem!