Fatal error when uploading flat file via the data integration file

Dear community,

Would you please have the pleasure to help me with my following issue?

I have created a compound MDT for which I want to to upload some master data via an excel file through the data integration tile. In the past I had managed to successfully upload this master data without any errors, but now that I want to update the data that I had uploaded, I come up with an error that says :

"coulld not read file for batch ID 156, unable to read file. Reason: Fatal error. More info in table /IBP/IMTLOG"

Would anybody please interpret this error?

Thank you very much for your time

Kind regards

Vasilis