[X4U] Playstation won't play iDVD-burnt disc

[net kat]

Sony playstation...

We use a playstation to play DVD movies here...it works pretty well,  
with the controller acting as the remote to skootch around the disc.
Anyway, I burned a home movie here using iDVD, and the Playstation  
sez the disc is "unreadable."

Now, considering that store-bought DVDs play fine on the Playstation,  
does this episode mean there's something wrong wtih my DVD? Plays ok  
on the Mac Mini that burnt it.

thanks for any ideas.

nk