How is the scanning laser controlled? Is it via GPIB, serial, or through analog/digital lines? If it's GPIB or serial you do not need NI-DAQ, as that is software used with NI data acquisition (analog in/out, digital in/out boards). In this case you just need NI-VISA. If it is controlled via analog/digital lines you would want to use DAQmx, which is the replacement for NI-DAQ legacy. The latter is kept around for those who have the older, non-DAQmx boards. If you have a newer board you will likely have a DAQmx board.
You mentioned "installation of the drivers for connecting the LabVIEW software to the Polytec one". I'm not sure what you mean by this. Do you actually have drivers for that instrument? Did you get them from NI, or from Polytec? Or, are you referring to the drivers for the hardware layer, such as VISA?