Panasonic DMR-EZ28 problem playing JPEGs

I have a DVD-R disc with many folders in it and it contains literally thousands of files in total. The folders vary in the number of files they contain. The files are JPEG and WVM/AVI files. Some are edited (mainly using Corel PhotoPaint 9 or 11) and some are unedited originals downloaded from the internet. The disc was burned using Nero Ultra 6.x with book type DVD-ROM and as a multi-session disc.

When I place them in my DMR-EZ28 recorder/player, I only see four folders and nothing else. What is the problem here? I have emailed Panasonic support and they responded by recommending that I use DVD-RAM discs but DVD-RAM discs are very hard to find on the market.

What are the specs for playing DVD-R or +R and JPEGs? Is it a problem because I have a “mixed” disc of videos and photos?

Any help would be appreciated.