I have a DVD Studio Pro disc I have created and burnt successfully on my iMAC but when the client is viewing it on a PC using either Windows Media, Winamp or VLC Media player it is not working.

I shot the material with the Sony EX1 in 1080p and have created the SD DVD in PAL using DVD Studio Pro.

Any suggestions on where I might be going wrong?

Does it play correctly in a standard DVD player? If so, then it's a computer software issue. Might need to upgrade the software.

Did you test the DVD before you gave it to the client?
If so, how?
-C

Simon: your client should be using a software DVD player on the PC, NOT a media player such as the ones you've listed.

I guess my essential question is that creating a SD DVD via DVD Studio Pro should be able to be played cross platform. For example when I have bought a DVD from say Amazon this plays on my Mac, PC and DVD Player connected to the TV. I assume that creating a DVD as I have done should do the same.

Simon,

Contrary to what most think, Windows does NOT come with DVD playback software built-in. Your client needs to purchase DVD playback software that conforms to the standard ISO DVD image playback. VLC will not reliably play DVD content. You cannot guarantee playback on all devices no matter what you do because you can't control what software your end-users may or may not have.

Contrary to what most think, Windows does NOT come with DVD playback software built-in. It all depends what version of Windows you have Vista Home Premium & Vista Ultimate do come with DVD playback capability as does Windows XP Media Center.
Your client needs to purchase DVD playback software that conforms to the standard ISO DVD image playback.Most manufacturers nowadays install a DVD player like WinDVD or PowerDVD so it is most likely that the Windows machine will be capable of playing a DVD.
VLC will not reliably play DVD content.Modern versions of VLC on Windows play DVDs very reliably.

Notwithstanding all the above it should be double checked that the Windows PC really is capable of playing a DVD as even with the correct player & CODEC installed it may have some configuration problem that prevents playback.

INCREDIBLY STUPID QUESTION:
The computer in question DOES HAVE a DVD drive installed and not just a CD-Rom, right?

The ONLY reason I ask is because in my former 9 - 5 we reauthored a disc 4 times(!!!) before I asked the client to bring in the "offending" laptop, which turned out to have a CD-Rom drive in it.

I'm not kidding...

No question is too stupid.

Answer not sure. Since client is in another city.