The first time I ran your VI without error. I ran the VI again with a bad sheet name and got the exact same error code.
It seems that your workbook does not contain a sheet with the name specified. There is no provision for trapping this condition. If the sheet is not found, the Search 1D Array function will return -1, and an index of 0 is invalid.
Michael
Certified LabVIEW Developer
www.abcdefirm.com