I'm guessing you installed the IVI driver for the Agilent signal generator. Based on the error, it is likely that you do not have VISA (or some other dependent software component) installed on your system. When VISA is not present on a system, the IVI engine fails to load. This causes functions that use the IVI engine error -1074135040 (xBFFA0000). You can download NI-VISA from NI's support and downloads page.
