3d printing colour sandstone unable to process

Hi Im trying to prepare a file for 3d printing in colour sandstone.Everytime I upload it it says "We're unable to process this file. Check your file for errors and click 'Update File' to upload a new version".I have checked it and i cant find any problems. I have also looked at all the tutorials on uploading vrml on your website.I even tried a basic cube to test on a simple model before trying my more complicated ones and it still isnt working.I am using Blender

thank you
sarah

...possibly choosen the wrong name of the png-file?

As kaadesign wrote - though I am not sure how or why his corrected version of the file got such an involved filename for the png texture.
The trick is simply that the texture filename as written in the wrl should not contain any drive letters or folder names - vrml is readable text, so you can simply open it in a text editor to check and correct the imageTexture entry. Your file had
where it should be simply