The problem turned out to an invalid Connecction String in the Excel properties dialog box. I am not sure how it was changed but it was referencing the MS-ACCESS ODBC driver and not the EXCEL ODBC driver.
The problem was solved by redefining the query over from scratch. It could have been solved by rewriting the connection string but in this case it was easier just to remove the old query and redefine it. See attached graphic with the correct connection string after the correction.
I am assigning point to Tim since the article he referenced indicated that ISAM problems are usually associated with MS-ACCESS databases. That piece if inofrmation pushed me to look at the connection string which ultimatley helped me solve the problem.
Jerry
