Red X for preview?

Hi All,
I've searched high and low for anyone with a similar problem but I can't find anyone with the same issues! On my local machine, when I run Gallery Remote, whenever I select photos to be uploaded, I cannot preview or rotate them.

They upload fine, connection to my gallery server is all good. But I just can't view the thumbnails, they all appear as a box with a red X in them. See the attached picture.

Interestingly, when I use Gallery remote from another computer at work, all is fine and I can view and rotate as I please. I did download the full package, including the packaged VM....

Any thoughts?

Whiplash