Thank you for your post.
I just imported a tab-delimited file with 250 fields, and it worked properly. In the Import dialog box, I am able to see the data match up as I skip through the records before clicking "Import". Also, make sure all fields are selected to be imported. If you select a subset of fields, then only data will be imported into those fields.
If you are still having difficulty, then I would like to see the file. I have sent you a private message (top of this page - right side - X Messages) with instructions where to send the text file.
Also, could it be that there is a return or newline character in a field in one of the lines? FM will interpret this as a new record.
Is it importing into a table view? Might there be a limit only on what it is displaying in table view? To chec, switch to form view and see if all the data is there.