Issue loading flat file into SAP BI using DTP

Hello

This is the first time that I have tried to create transformations and a DTP. I have a flat file that has three text fields in the file that I do not want to import. When I try to load to the PSA I get the following message; "

"Error 'The argument 'PO QTY' cannot be interpreted as a number' on assignment field /BIC/ZQUANTITY record 1 value PO QTY" Message no. RSDS013. I have double checked the DataSource, flat file and DTP layouts. I have verified that the dataSource, DTP and flat file layout match.

I know that this means that it is trying to read the first text field into the quantity field. How do I preview this? Have I missed a step in the process?

Any help at all is greatly appreciated.

Renee