We had the same problem with our SQL Server 2005 64 bit server. After some research, it seems that Microsoft got rid of their OLE DB Provider for ODBC Drivers. We purchased the OpenLink OleDB Provider for ODBC from Openlink Software for a minimal fee.
http://uda.openlinksw.com/odbc/st/odbc-mysql-st/
http://download.openlinksw.com/download/download.vsp
We had a few issues at first, but their support was great and we didn't even purchase the extra support.
Wendy Schuman