In EMC9 once I make a photo slideshow (230 photos + 5 audio tracks)
The burning process goes alright ie. all the data is on the disc but when i play it back it gets to chapter 99 then jumps to 199.
I have mixed up the photos and audio incase of corrupt file, but this isn't the case.
I have tried to find if there is a break in the slideshow, looking on the timeline and storyline but I can't see anything

You'll have your best results using Video Wave to create the slide show and save it as a project. Close VideoWave and then use MyDVD add the project and then burn (encode) to an ISO file. Once the ISO is complete, use Disc Copier to preview the ISO file and to copy it to a disc.

If you used the 3 step Slide Show Assistant, you can take the production from the Assistant to Video Wave in the third step and do your final editing there. The 2 step in My DVD will not allow you to do that (I believe).

Since you didn't list your computer specs, the following are general suggestions to help. Make sure your computer is free of malware and your hard drive is defragged. When you are working with any kind of video work, it is also best to shut down all other running programs including your anti-virus (of course, disconnect from the internet). Use good quality DVD blanks. In the past, Memorex and store brand discs have given problems.

To sknis, I took your advice and went through Video Wave instead of Slide Show Assistant (which is where I've been for about 3 weeks) and I have managed work it out. I am very appreciative of your help as I have been going round in circles for ages, thanks.