"A Surface is Using a Texture That Can't be Found" Message

[larq]

I'm using HDS8.0.

Since I have imported some images of my own into my plan (photographs of my own), everytime I open 3D view, a box pops up with the message "A Surface is Using a Texture That Can't be Found". I click the box to not show this message again in that session, which is fine, but the next time I open 3D there it is again. What does this message mean and how can I stop this message from popping up every time I open 3D? Thanks.