Congratulations on Aspose Slides v.3 which is a great improvement!
However, when cloning PPTX slides we run into one of the following errors with most presentation files:-
1) Error cloning slide (slide 1 of 1) 2) Error reading pptslidesslide1.xml xml part (slide 0 of 0) 3) Object reference not set to an instance of an object. (slide 1 of 1), and 4) Value was either too large or too small for an Int32. (slide 0 of 0)
Some errors are caused by the presence of Page numbering on the slides but others occur with blank slides. In these cases the problems seem to reside with the Slide Masters.
Please find 9 small presentations attached (as a ZIP file) with each error described on the slide in question. Each folder is named in line with the error type. Also note than sometimes the first slide will have been set to #0 instead of #1 by its owner (a strange but common practice).
Please let me know if you need furthr information?
Well, it's a good start, several errors are fixed and the Custom Animation is working well - great! However, we can't get much further until the 'Object Reference errors..' and 'Cloning errors' can be eliminated.
Now, here's a weird one concerned with PPTX 'elbow connectors'. In the attached file the slide will clone provided all the elbow connectors have already been connected (see file 'Last elbow connector connected.pptx'). If one has not yet been connected it causes a 'Object reference not set to an instance of an object. (slide 0 of 0)' error - see file 'All but 1 elbow connector connected.pptx'.
However, it's no good disconnecting one afterwards because it then clones OK, even though there is a disconnection. This happens only when at least one elbow remains to be connected for the first time. Enjoy!