I used to get split files regularly with winavi 6.3 to the extent that I always have 2 windows open (tile windows vertically) when processing:
1 - the folder where winavi puts its folder(s), and
2 - the video_ts folder.
In the first I will see immediately if winavi has split the output over 2 dvd's, and in the second I will see the vob file names to make sure I have chosen the setup I want (one title or separate titles).
I have to say though that I don't think I have had a split file incident since I changed to winavi 8.
But the sequence is quite clear: it asks you to 'add files' and after files are added the burn button is available and you burn - so long as you have a disk inserted...
Over the past 2-3 weeks I went from 6.3 to 7 (can't remember which) now 8.
I use(d) all with speed setting. I think 8 is quicker, although I have not timed.
I never bothered with menus before, but now with 8 it is automatic unless you turn it off and I have decided I like them. The actual menus are very attractive and usable, better than the menus you get on commercial dvds.
If you go to the free download page at the winavi site there is a button called 'resource', click it and you will see downloads, presumably it is one of those?
What is the overall size of the input file? There is a relationship between the size of input and output, and this is affected by the selected quality option. If you end up with something too big you can always use dvdshrink.
It's doing this because you are generating an output that is greater than your chosen size of dvd. Could be you are trying to cram in too many avi's (or whatever) or trying for a very high quality dvd.
You could try less avi's or lower quality. Also try changing (at the page you get to after selecting files to be converted - click on 'Advanced') the size of dvd - increase from 4300 to 4700 say. If then you can't write it to dvd because your file is too big, use dvdshrink. I always keep 2 folders open when I am converting (tile windows vertically) - the video ts_file folder so that I can see the vob files names to be sure I am creating separate or merged titles, whichever I have chosen (or was supposed to choose) - and also the folder where I can see how many folders are being created (dvd0, dvd1).
When you are burning the disk what option are you choosing? Could be you are burning as a data disk instead of choosing 'new video dvd' (or similar). If burn data dvd it will not play in dvd player either I think.
By the way, I see from your other post that you are using dvd-rw. I gave up on these because they would not play in my computer. You could try +rw see if that works. I keep the -rw for data or audio now.
Your selected input files are resulting in an output file that is too big for the dvd size you have selected.
Two possibilities: 1 you have chosen high quality - which will result in a bigger file - option: choose a lower quality 2 you are trying to include too many avis (or whatever) and the overall input size is too big: option make 2 dvd's instead of 1.
The screen you get to after you have selected the files for conversion has a button 'Advanced' - if you click this you will see options to choose the dvd size (4300, 4700 and 8500 I think) and another option to choose quality or speed. Other options also. If you decide to stick with whatever options you already have 'high quality' or 'loads of avi's' you could choose a bigger dvd size, say 4700 instead of 4300 or even choose 8500. After if you have a problem fitting on dvd you could use dvdshrink. You might need to tinker a little, maybe even dvdshrink twice.
Please note that the foregoing assumes that you have 2 folders with 2 sets of dvd files: it just occorred to me you may mean that you have 2 vob files in 1 folder. If this is the case it is again because the output file exceeds the maximum size of a vob file and 2 are needed. You won't see any break when playing back.
I would always advise to use dvd rw disks when experimenting or getting to know new software - saves coasters!