You put lots of effort into this. Here's what was done to make it preview, so a screen grab could be made...
1. Audio tracks were consolidated into 1
2. Unused effects (mask, motion) were removed from every track
3. Track 26 contents were moved to track 25
3. An 800x450 screen grab was made in lieu of export
No, it's not ideal, but usable
In our Messenger discussion you will find a link to the screen grab, from your original, and a link to the rebuilt project using the suggested 5x5 grid. That one should export at up to 1080, very slowly. When compared with positioning each box individually, grids are a breeze.
A high number of tracks/effects can max out 32-bit app memory. Generally, and this applies not only to Videopad, fewer tracks and effects = fewer problems.
Compound effects can be pre-produced, then exported, to lower processing load. Then those composited clips can be added to the final edit. Essentially that's what Nat suggests in a method he outlines in the 'choir' sticky post at the top of this forum.