Are you installing an upgrade version or full version NI-FBUS 2.3.6 software? If it is an upgrade version, you should close all the NI-FBUS programs and restart PC, then upgrade; if you have a full installer, you need to uninstall the old version and restart machine then install new NI-FBUS software.
Please check whether the driver file "nifb.sys" exists under "System32\Drivers" directory? If no, please uninstall NI-FBUS, restart your machine and install it again. Make sure you have installed software before you insert PCMCIA-FBUS card.
If it doesn't work, please contact "fieldbus.support@ni.com" for further help.