A DVD that only runs on some players

I have question about DVD limits.

http://en.wikibooks.org/wiki/Inside_DVD-Video/Limits

I have a set of 3 webcams monitoring motion events outside the house. I 
use a perl script and DVDStyler to produce a DVD with 4 months of daily 
motion movies. the structure is:

VGM:
    Select Month in Year

Titleset 1: (first month)
    Select Day on Month menu: 28-31 day buttons + 1 Back (to VGM) button
    28-31 Titles
        Each Title consists of 3 VOB references pointing to the a 
camera's daily movie.

Titleset(s) 2-4: (same as Titleset 1)

The problem is that the DVD is produced, but only works on some players. 
I have a older Philips DVD player that works fine. My newer Sony Blu-Ray 
player basically "hangs" on it and I have to power cycle it to get it to 
spit out the DVD. Every PC-based player I have tried also works fine. A 
friend with a newer DVD player has problems.

Using the DVD limits reference, I believe I am just under the 
menu-button limit of 36 for narrow screen. All the the movies and menus 
are 4:3.  The other concern is 99 titles in a titleset, but even if a 
VOB is counted as a title, I never have more than 93.

So have I exceeded some limit I am unaware of, or is the Sony player 
deficient? Or is the "but only 12 [buttons per menu] at once for 
widescreen" biting me with the newer player as they are always widescreen?

Here are some xml snippets:

<titleset>
<menus>
<video aspect="4:3"/>
<audio lang="EN"/>
<subpicture lang="EN"/>
<pgc entry="root">
<button name="button1">g0=button;jump title 1;</button>
<button name="button2">g0=button;jump title 2;</button>
<button name="button3">g0=button;jump title 3;</button>
          :
<button name="button31">g0=button;jump vmgm menu 2;</button>
<vob 
file="/home/pwalden/Videos/DVDProjects/webcam/2011-09-12/dvd-tmp/menu1-0.mpg"/>
<pre>if (g1==1 and g0&gt;0) button = g0; else button = 1024;g1=1;</pre>
</pgc>
</menus>
<titles>
<video aspect="4:3"/>
<audio lang="EN"/>
<pgc>
<vob chapters="1:00,2:00,3:00,4:00,5:00,6:00,7:00,8:00,9:00" 
file="/opt2/pwalden/webcam/cam1/2011/09/01/01.mpg"/>
<vob chapters="1:00,2:00,3:00,4:00,5:00,6:00,7:00,8:00,9:00" 
file="/opt2/pwalden/webcam/cam2/2011/09/01/01.mpg"/>
<vob chapters="1:00,2:00,3:00,4:00,5:00,6:00,7:00,8:00,9:00" 
file="/opt2/pwalden/webcam/cam3/2011/09/01/01.mpg"/>
<post>g1 = 0;call menu;</post>
</pgc>
<pgc>
<vob chapters="1:00,2:00,3:00,4:00,5:00,6:00,7:00,8:00,9:00" 
file="/opt2/pwalden/webcam/cam1/2011/09/02/02.mpg"/>
<vob chapters="1:00,2:00,3:00,4:00,5:00,6:00,7:00,8:00,9:00" 
file="/opt2/pwalden/webcam/cam2/2011/09/02/02.mpg"/>
<vob chapters="1:00,2:00,3:00,4:00,5:00,6:00,7:00,8:00,9:00" 
file="/opt2/pwalden/webcam/cam3/2011/09/02/02.mpg"/>
<post>g1 = 0;call menu;</post>
</pgc>
        : etc


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