The error is generally received when two programs try to access an image acquisition device at the same time. For example, if you have the device selected in Measurement & Automation Explorer(MAX) and are trying to perform an image acquisition in a VI, you will receive this message. You must deselect the acquisition device in MAX or close MAX in order for your VI to run correctly.
This error can also occur when using IMAQ functions with an unwired IMAQ session. If an IMAQsession is initiazed but not passed to the IMAQ Gab/Snap/Sequence function, a second session will be created resulting in Error -1074396995. Make sure that only one IMAQ session is created and referenced correctly in your application.