Could the excerpt from your message below be your issue? Did you verify your default Excel save format.
From: midrange-l-bounces@xxxxxxxxxxxx [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Steinmetz, Paul
Sent: Thursday, April 17, 2014 9:12 AM
To: 'Midrange Systems Technical Discussion'
Subject: Excel - IBM I Access Data Transfer error at 64,000 rows - CWBTF0012
It has also been reported that even after V5R4 service pack SI31388, downloads in Excel 2007 of more then 65,536 rows may fail with message CWBTF0012 - An unexpected error has been detected while processing transfer request. This error occurred when the default Excel save format was Excel 97-2003 workbook (*.xls) instead of Excel Workbook (*.xlsx). This default setting can be changed from within Excel 2007/2010.
You can change the file type that is used by default when you save a workbook:
1. On the File tab, click Options.
2. In the Save category, under Save workbooks, in the Save files in this format box, click the file format that you want to use by default.