Hi!
From what you describe it seems the problem is the same as the last time: when Shapespark extension requests SketchUp to extract a texture from the .skp model and save the texture to a file, so that it could be imported to Shapespark, the saved texture file is for some reason corrupted.
The information about which texture is problematic can be read from the Shapespark application log files, which reside in C:\Users\<YOUR-USER>\AppData\Local\Shapespark\log.
Could you submit a problem report from the “Help & Support” tab. We will take a look at the logs attached to the report, and point you to the particular log entry which refers to the corrupted texture.
Could you also send us the .skp file, so we could try reproducing the error. The last time we were unable to reproduce it, so it seems the error may be related to your particular version or installation of SketchUp… What version of SketchUp does the Help > About menu shows?