Hi Orel,
First, thank you for posting your solution, it will certainly help other users who may come across this problem in the future.
Secondly, please create new posts for new questions. You are getting this error though because you need to call "IMAQ Create" to create a buffer in memory for the image. Image data types in LV are actually pointers to this buffer, and not the actual image data (because they are so large it would be cumbersome to pass around all that data).
Use create image and dispose image to deal with these image data types.
Cheers!
Marti C
Applications Engineer
National Instruments
NI Medical