Are you trying to use a 32-bit API with a 64-bit version of Labview?
I just tried it with LV64-bit 2020. Similar errors you show. Followed their instructions and seems fine.
2.2.3.2 Windows with 64-bit Labview
C:\Program Files\National Instruments\LabVIEW 2016\instr.lib
In the Signal Hound driver folder, you will need to rename the 64-bit DLL and either delete or rename the 32-bit DLL.
For example, for the BB series, rename bb_api.dll to bb_api-32.dll, and rename bb_api-64.dll to bb_api.dll.
