I have a flat jpg image (3600 x 584) stuck together with 6 different perimeter views from a regular (equirectangular) lens. I'm trying to make a panorama image from it using either PTGui or Microsoft Image Composite Editor. PTGui gives me an "ImageFormatException Unsupported color conversion request" error because there's no EXIF data, and ICE stitches the 6 views together but the resulting image is not right.
To use a stitching application the images need features that overlap enough to allow the software to extrapolate a mapping for the rest of the image. Some software can attempt to find suitable matching points for you but you may also need to do it yourself.
Normally you'd also need the images to taken from approximately the same position.
Your problem here is that the images seem to neither have natural overlaps nor be taken from the same position.
This makes it unlikely you'll get this kind of software to do the job for you.